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vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Stops,_f-stop_conventions,_and_exposure"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Stops, f-stop conventions, and exposure</span> </div> </a> <button aria-controls="toc-Stops,_f-stop_conventions,_and_exposure-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Stops, f-stop conventions, and exposure subsection</span> </button> <ul id="toc-Stops,_f-stop_conventions,_and_exposure-sublist" class="vector-toc-list"> <li id="toc-Fractional_stops" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fractional_stops"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Fractional stops</span> </div> </a> <ul id="toc-Fractional_stops-sublist" class="vector-toc-list"> <li id="toc-Standard_full-stop_f-number_scale" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Standard_full-stop_f-number_scale"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1.1</span> <span>Standard full-stop f-number scale</span> </div> </a> <ul id="toc-Standard_full-stop_f-number_scale-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Typical_one-half-stop_f-number_scale" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Typical_one-half-stop_f-number_scale"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1.2</span> <span>Typical one-half-stop f-number scale</span> </div> </a> <ul id="toc-Typical_one-half-stop_f-number_scale-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Typical_one-third-stop_f-number_scale" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Typical_one-third-stop_f-number_scale"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1.3</span> <span>Typical one-third-stop f-number scale</span> </div> </a> <ul id="toc-Typical_one-third-stop_f-number_scale-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Typical_one-quarter-stop_f-number_scale" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Typical_one-quarter-stop_f-number_scale"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1.4</span> <span>Typical one-quarter-stop f-number scale</span> </div> </a> <ul id="toc-Typical_one-quarter-stop_f-number_scale-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-H-stop" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#H-stop"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>H-stop</span> </div> </a> <ul id="toc-H-stop-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-T-stop" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#T-stop"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>T-stop</span> </div> </a> <ul id="toc-T-stop-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-ASA/ISO_numbers" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#ASA/ISO_numbers"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>ASA/ISO numbers</span> </div> </a> <ul id="toc-ASA/ISO_numbers-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Gain" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Gain"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>Gain</span> </div> </a> <ul id="toc-Gain-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Sunny_16_rule" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Sunny_16_rule"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.6</span> <span>Sunny 16 rule</span> </div> </a> <ul id="toc-Sunny_16_rule-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Effects_on_image_sharpness" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Effects_on_image_sharpness"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Effects on image sharpness</span> </div> </a> <ul id="toc-Effects_on_image_sharpness-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Human_eye" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Human_eye"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Human eye</span> </div> </a> <ul id="toc-Human_eye-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Focal_ratio_in_telescopes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Focal_ratio_in_telescopes"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Focal ratio in telescopes</span> </div> </a> <ul id="toc-Focal_ratio_in_telescopes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Camera_equation_(G#)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Camera_equation_(G#)"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Camera equation (G#)</span> </div> </a> <ul id="toc-Camera_equation_(G#)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Working_f-number" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Working_f-number"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Working f-number</span> </div> </a> <ul id="toc-Working_f-number-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>History</span> </div> </a> <button aria-controls="toc-History-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle History subsection</span> </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Origins_of_relative_aperture" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Origins_of_relative_aperture"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.1</span> <span>Origins of relative aperture</span> </div> </a> <ul id="toc-Origins_of_relative_aperture-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Aperture_numbering_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Aperture_numbering_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.2</span> <span>Aperture numbering systems</span> </div> </a> <ul id="toc-Aperture_numbering_systems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Typographical_standardization" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Typographical_standardization"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.3</span> <span>Typographical standardization</span> </div> </a> <ul id="toc-Typographical_standardization-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left"> <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents"> <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true"><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading">f-number</h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang"> <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 35 languages"> <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-35" aria-hidden="true"><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">35 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://af.wikipedia.org/wiki/F-nommer" title="F-nommer – Afrikaans" lang="af" hreflang="af" data-title="F-nommer" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://ar.wikipedia.org/wiki/%D8%B9%D8%AF%D8%AF_%D8%A7%D9%84%D8%A8%D8%A4%D8%B1%D8%A9" title="عدد البؤرة – Arabic" lang="ar" hreflang="ar" data-title="عدد البؤرة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://bn.wikipedia.org/wiki/%E0%A6%8F%E0%A6%AB-%E0%A6%A8%E0%A6%BE%E0%A6%AE%E0%A7%8D%E0%A6%AC%E0%A6%BE%E0%A6%B0" title="এফ-নাম্বার – Bangla" lang="bn" hreflang="bn" data-title="এফ-নাম্বার" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://be-tarask.wikipedia.org/wiki/%D0%9B%D1%96%D0%BA_%D0%B4%D1%8B%D1%8F%D1%84%D1%80%D0%B0%D0%B3%D0%BC%D1%8B" title="Лік дыяфрагмы – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Лік дыяфрагмы" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://bg.wikipedia.org/wiki/%D0%9E%D1%82%D0%BD%D0%BE%D1%81%D0%B8%D1%82%D0%B5%D0%BB%D0%BD%D0%B0_%D0%B0%D0%BF%D0%B5%D1%80%D1%82%D1%83%D1%80%D0%B0" title="Относителна апертура – Bulgarian" lang="bg" hreflang="bg" data-title="Относителна апертура" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://ca.wikipedia.org/wiki/Nombre_f" title="Nombre f – Catalan" lang="ca" hreflang="ca" data-title="Nombre f" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://cs.wikipedia.org/wiki/Clonov%C3%A9_%C4%8D%C3%ADslo" title="Clonové číslo – Czech" lang="cs" hreflang="cs" data-title="Clonové číslo" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de badge-Q70894304 mw-list-item" title=""><a href="https://web.archive.org/web/20241119105220/https://de.wikipedia.org/wiki/Blendenzahl" title="Blendenzahl – German" lang="de" hreflang="de" data-title="Blendenzahl" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://el.wikipedia.org/wiki/%CE%91%CF%81%CE%B9%CE%B8%CE%BC%CF%8C%CF%82_%CE%B4%CE%B9%CE%B1%CF%86%CF%81%CE%AC%CE%B3%CE%BC%CE%B1%CF%84%CE%BF%CF%82_%CE%B1%CE%BD%CE%BF%CE%AF%CE%B3%CE%BC%CE%B1%CF%84%CE%BF%CF%82" title="Αριθμός διαφράγματος ανοίγματος – Greek" lang="el" hreflang="el" data-title="Αριθμός διαφράγματος ανοίγματος" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://es.wikipedia.org/wiki/N%C3%BAmero_f_(%C3%B3ptica)" title="Número f (óptica) – Spanish" lang="es" hreflang="es" data-title="Número f (óptica)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://eo.wikipedia.org/wiki/Relativa_truo_de_objektivo" title="Relativa truo de objektivo – Esperanto" lang="eo" hreflang="eo" data-title="Relativa truo de objektivo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://eu.wikipedia.org/wiki/F_zenbakia_(optika)" title="F zenbakia (optika) – Basque" lang="eu" hreflang="eu" data-title="F zenbakia (optika)" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://fa.wikipedia.org/wiki/%D8%B6%D8%B1%DB%8C%D8%A8_%D8%A7%D9%81" title="ضریب اف – Persian" lang="fa" hreflang="fa" data-title="ضریب اف" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://fr.wikipedia.org/wiki/Ouverture_(photographie)" title="Ouverture (photographie) – French" lang="fr" hreflang="fr" data-title="Ouverture (photographie)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://ga.wikipedia.org/wiki/F-uimhir" title="F-uimhir – Irish" lang="ga" hreflang="ga" data-title="F-uimhir" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://ko.wikipedia.org/wiki/F_%EA%B0%92" title="F 값 – Korean" lang="ko" hreflang="ko" data-title="F 값" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://hy.wikipedia.org/wiki/%D5%80%D5%A1%D6%80%D5%A1%D5%A2%D5%A5%D6%80%D5%A1%D5%AF%D5%A1%D5%B6_%D5%A1%D5%B6%D6%81%D6%84" title="Հարաբերական անցք – Armenian" lang="hy" hreflang="hy" data-title="Հարաբերական անցք" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://hi.wikipedia.org/wiki/%E0%A4%AB%E0%A5%8B%E0%A4%95%E0%A4%B8_%E0%A4%85%E0%A4%A8%E0%A5%81%E0%A4%AA%E0%A4%BE%E0%A4%A4" title="फोकस अनुपात – Hindi" lang="hi" hreflang="hi" data-title="फोकस अनुपात" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://id.wikipedia.org/wiki/Bukaan_(fotografi)" title="Bukaan (fotografi) – Indonesian" lang="id" hreflang="id" data-title="Bukaan (fotografi)" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://web.archive.org/web/20241119105220/https://is.wikipedia.org/wiki/Lj%C3%B3sop" title="Ljósop – Icelandic" lang="is" hreflang="is" data-title="Ljósop" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a 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dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Measure of lens speed</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For other uses, see <a href="/web/20241119105220/https://en.wikipedia.org/wiki/F-number_(disambiguation)" class="mw-disambig" title="F-number (disambiguation)">F-number (disambiguation)</a>.</div> <p class="mw-empty-elt"> </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Aperture_diagram.svg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Aperture_diagram.svg/320px-Aperture_diagram.svg.png" decoding="async" width="320" height="128" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Aperture_diagram.svg/480px-Aperture_diagram.svg.png 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Aperture_diagram.svg/640px-Aperture_diagram.svg.png 2x" data-file-width="512" data-file-height="204"/></a><figcaption>Diagram of decreasing <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture" title="Aperture">apertures</a>, that is, increasing f-numbers, in one-stop increments; each aperture has half the light-gathering area of the previous one.</figcaption></figure> <p>An <b>f-number</b> is a measure of the light-gathering ability of an optical system such as a <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera_lens" title="Camera lens">camera lens</a>. It is calculated by dividing the system's <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">focal length</a> by the diameter of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Entrance_pupil" title="Entrance pupil">entrance pupil</a> ("clear <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture" title="Aperture">aperture</a>").<sup id="cite_ref-ReferenceA_1-0" class="reference"><a href="#cite_note-ReferenceA-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> The f-number is also known as the <b>focal ratio</b>, <b>f-ratio</b>, or <b>f-stop</b>, and it is key in determining the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_field" title="Depth of field">depth of field</a>, <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diffraction" title="Diffraction">diffraction</a>, and <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_(photography)" title="Exposure (photography)">exposure</a> of a photograph.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> The f-number is <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Dimensionless_number" class="mw-redirect" title="Dimensionless number">dimensionless</a> and is usually expressed using a lower-case <a href="/web/20241119105220/https://en.wikipedia.org/wiki/%C6%91" title="Ƒ">hooked f</a> with the format <style data-mw-deduplicate="TemplateStyles:r1207775266">.mw-parser-output span.fnumber,.mw-parser-output .fnumber-fallback{display:inline-block;white-space:nowrap;width:max-content}.mw-parser-output span.fnumber::first-letter,.mw-parser-output .fnumber-fallback .first-letter{font-style:italic;font-family:Trebuchet MS,Candara,Georgia,Calibri,Corbel,serif}</style><span class="fnumber-fallback"><span class="first-letter">f</span>/</span><i>N</i>, where <i>N</i> is the f-number. </p><p>The f-number is also known as the <b>inverse relative aperture</b>, because it is the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Multiplicative_inverse" title="Multiplicative inverse">inverse</a> of the <b>relative aperture</b>, defined as the aperture diameter divided by focal length.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> The relative aperture indicates how much light can pass through the lens at a given focal length. A lower f-number means a larger relative aperture and more light entering the system, while a higher f-number means a smaller relative aperture and less light entering the system. The f-number is related to the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Numerical_aperture" title="Numerical aperture">numerical aperture</a> (NA) of the system, which measures the range of angles over which light can enter or exit the system. The numerical aperture takes into account the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Refractive_index" title="Refractive index">refractive index</a> of the medium in which the system is working, while the f-number does not. </p> <meta property="mw:PageProp/toc"/> <div class="mw-heading mw-heading2"><h2 id="Notation">Notation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=1" title="Edit section: Notation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The f-number <span class="texhtml mvar" style="font-style:italic;">N</span> is given by: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N={\frac {f}{D}}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mi>D</mi> </mfrac> </mrow> <mtext> </mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N={\frac {f}{D}}\ }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/5f77eef5650185f41f729e3b0c6fd1fc1aea1f22" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:8.503ex; height:5.343ex;" alt="{\displaystyle N={\frac {f}{D}}\ }"></span> </p><p>where <span class="texhtml mvar" style="font-style:italic;">f</span> is the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">focal length</a>, and <span class="texhtml mvar" style="font-style:italic;">D</span> is the diameter of the entrance pupil (<i>effective aperture</i>). It is customary to write f-numbers preceded by "<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/</span>", which forms a mathematical expression of the entrance pupil's diameter in terms of <span class="texhtml mvar" style="font-style:italic;">f</span> and <span class="texhtml mvar" style="font-style:italic;">N</span>.<sup id="cite_ref-ReferenceA_1-1" class="reference"><a href="#cite_note-ReferenceA-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> For example, if a <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lens_(optics)" class="mw-redirect" title="Lens (optics)">lens's</a> focal length were <span class="nowrap"><span data-sort-value="6999100000000000000♠"></span>100 mm</span> and its entrance pupil's diameter were <span class="nowrap"><span data-sort-value="6998500000000000000♠"></span>50 mm</span>, the f-number would be 2. This would be expressed as <span class="nowrap">"<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2</span>"</span> in a lens system. The aperture diameter would be equal to <span class="texhtml"><i>f</i>/2</span>. </p><p>Camera lenses often include an adjustable <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diaphragm_(optics)" title="Diaphragm (optics)">diaphragm</a>, which changes the size of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture_stop" class="mw-redirect" title="Aperture stop">aperture stop</a> and thus the entrance pupil size. This allows the user to vary the f-number as needed. The entrance pupil diameter is not necessarily equal to the aperture stop diameter, because of the magnifying effect of lens elements in front of the aperture. </p><p>Ignoring differences in light transmission efficiency, a lens with a greater f-number projects darker images. The brightness of the projected image (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Illuminance" title="Illuminance">illuminance</a>) relative to the brightness of the scene in the lens's field of view (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Luminance" title="Luminance">luminance</a>) decreases with the square of the f-number. A <span class="nowrap"><span data-sort-value="6999100000000000000♠"></span>100 mm</span> focal length <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span> lens has an entrance pupil diameter of <span class="nowrap"><span data-sort-value="6998250000000000000♠"></span>25 mm</span>. A <span class="nowrap"><span data-sort-value="6999100000000000000♠"></span>100 mm</span> focal length <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2</span> lens has an entrance pupil diameter of <span class="nowrap"><span data-sort-value="6998500000000000000♠"></span>50 mm</span>. Since the area is proportional to the square of the pupil diameter,<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> the amount of light admitted by the <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2</span> lens is four times that of the <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span> lens. To obtain the same <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_(photography)" title="Exposure (photography)">photographic exposure</a>, the exposure time must be reduced by a factor of four. </p><p>A <span class="nowrap"><span data-sort-value="6999200000000000000♠"></span>200 mm</span> focal length <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span> lens has an entrance pupil diameter of <span class="nowrap"><span data-sort-value="6998500000000000000♠"></span>50 mm</span>. The <span class="nowrap"><span data-sort-value="6999200000000000000♠"></span>200 mm</span> lens's entrance pupil has four times the area of the <span class="nowrap"><span data-sort-value="6999100000000000000♠"></span>100 mm</span> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span> lens's entrance pupil, and thus collects four times as much light from each object in the lens's field of view. But compared to the <span class="nowrap"><span data-sort-value="6999100000000000000♠"></span>100 mm</span> lens, the <span class="nowrap"><span data-sort-value="6999200000000000000♠"></span>200 mm</span> lens projects an image of each object twice as high and twice as wide, covering four times the area, and so both lenses produce the same illuminance at the focal plane when imaging a scene of a given luminance. </p> <div class="mw-heading mw-heading2"><h2 id="Stops,_f-stop_conventions,_and_exposure"><span id="Stops.2C_f-stop_conventions.2C_and_exposure"></span>Stops, f-stop conventions, and exposure</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=2" title="Edit section: Stops, f-stop conventions, and exposure"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Canon_7_with_50mm_f0.95_IMG_0374.JPG" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Canon_7_with_50mm_f0.95_IMG_0374.JPG/220px-Canon_7_with_50mm_f0.95_IMG_0374.JPG" decoding="async" width="220" height="220" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Canon_7_with_50mm_f0.95_IMG_0374.JPG/330px-Canon_7_with_50mm_f0.95_IMG_0374.JPG 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Canon_7_with_50mm_f0.95_IMG_0374.JPG/440px-Canon_7_with_50mm_f0.95_IMG_0374.JPG 2x" data-file-width="2730" data-file-height="2736"/></a><figcaption>A <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Canon_7" title="Canon 7">Canon 7</a> mounted with a <span class="nowrap"><span data-sort-value="6998500000000000000♠"></span>50 mm</span> lens capable of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/0.95</span></figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Lens_aperture_side.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Lens_aperture_side.jpg/220px-Lens_aperture_side.jpg" decoding="async" width="220" height="220" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Lens_aperture_side.jpg/330px-Lens_aperture_side.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Lens_aperture_side.jpg/440px-Lens_aperture_side.jpg 2x" data-file-width="1200" data-file-height="1200"/></a><figcaption>A <span class="nowrap"><span data-sort-value="6998350000000000000♠"></span>35 mm</span> lens set to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/11</span>, as indicated by the white dot above the f-stop scale on the aperture ring. This lens has an aperture range of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2</span> to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/22</span>.</figcaption></figure> <p>The word <i>stop</i> is sometimes confusing due to its multiple meanings. A stop can be a physical object: an opaque part of an optical system that blocks certain rays. The <i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture_stop" class="mw-redirect" title="Aperture stop">aperture stop</a></i> is the aperture setting that limits the brightness of the image by restricting the input pupil size, while a <i>field stop</i> is a stop intended to cut out light that would be outside the desired field of view and might cause flare or other problems if not stopped. </p><p>In photography, stops are also a <i>unit</i> used to quantify ratios of light or exposure, with each added stop meaning a factor of two, and each subtracted stop meaning a factor of one-half. The one-stop unit is also known as the EV (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_value" title="Exposure value">exposure value</a>) unit. On a camera, the aperture setting is traditionally adjusted in discrete steps, known as <i><b>f-stops</b></i>. Each "<b>stop</b>" is marked with its corresponding f-number, and represents a halving of the light intensity from the previous stop. This corresponds to a decrease of the pupil and aperture diameters by a factor of 1/<span class="nowrap">√<span style="border-top:1px solid; padding:0 0.1em;">2</span></span> or about 0.7071, and hence a halving of the area of the pupil. </p><p>Most modern lenses use a standard f-stop scale, which is an approximately <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Geometric_sequence" class="mw-redirect" title="Geometric sequence">geometric sequence</a> of numbers that corresponds to the sequence of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exponentiation" title="Exponentiation">powers</a> of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Square_root_of_2" title="Square root of 2">square root of 2</a>: <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1.4</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2.8</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/5.6</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/11</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/16</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/22</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/32</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/45</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/64</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/90</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/128</span>, etc. Each element in the sequence is one stop lower than the element to its left, and one stop higher than the element to its right. The values of the ratios are rounded off to these particular conventional numbers, to make them easier to remember and write down. The sequence above is obtained by approximating the following exact geometric sequence: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f/1={\frac {f}{({\sqrt {2}})^{0}}},\ f/1.4={\frac {f}{({\sqrt {2}})^{1}}},\ f/2={\frac {f}{({\sqrt {2}})^{2}}},\ f/2.8={\frac {f}{({\sqrt {2}})^{3}}},\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>1</mn> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msup> </mrow> </mfrac> </mrow> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>1.4</mn> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msup> </mrow> </mfrac> </mrow> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>2</mn> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mrow> </mfrac> </mrow> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>2.8</mn> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msup> </mrow> </mfrac> </mrow> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f/1={\frac {f}{({\sqrt {2}})^{0}}},\ f/1.4={\frac {f}{({\sqrt {2}})^{1}}},\ f/2={\frac {f}{({\sqrt {2}})^{2}}},\ f/2.8={\frac {f}{({\sqrt {2}})^{3}}},\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/cc386280321ff746234d3fbe04ddc3b6f1ee18ac" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.005ex; width:67.187ex; height:6.509ex;" alt="{\displaystyle f/1={\frac {f}{({\sqrt {2}})^{0}}},\ f/1.4={\frac {f}{({\sqrt {2}})^{1}}},\ f/2={\frac {f}{({\sqrt {2}})^{2}}},\ f/2.8={\frac {f}{({\sqrt {2}})^{3}}},\ \ldots }"></span> In the same way as one f-stop corresponds to a factor of two in light intensity, <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Shutter_speed" title="Shutter speed">shutter speeds</a> are arranged so that each setting differs in duration by a factor of approximately two from its neighbour. Opening up a lens by one stop allows twice as much light to fall on the film in a given period of time. Therefore, to have the same exposure at this larger aperture as at the previous aperture, the shutter would be opened for half as long (i.e., twice the speed). The film will respond equally to these equal amounts of light, since it has the property of <i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Reciprocity_(photography)" title="Reciprocity (photography)">reciprocity</a></i>. This is less true for extremely long or short exposures, where there is <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Reciprocity_failure" class="mw-redirect" title="Reciprocity failure">reciprocity failure</a>. Aperture, shutter speed, and film sensitivity are linked: for constant scene brightness, doubling the aperture area (one stop), halving the shutter speed (doubling the time open), or using a film twice as sensitive, has the same effect on the exposed image. For all practical purposes extreme accuracy is not required (mechanical shutter speeds were notoriously inaccurate as wear and lubrication varied, with no effect on exposure). It is not significant that aperture areas and shutter speeds do not vary by a factor of precisely two. </p><p>Photographers sometimes express other <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_(photography)" title="Exposure (photography)">exposure</a> ratios in terms of 'stops'. Ignoring the f-number markings, the f-stops make a <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Logarithmic_scale" title="Logarithmic scale">logarithmic scale</a> of exposure intensity. Given this interpretation, one can then think of taking a half-step along this scale, to make an exposure difference of a "half stop". </p> <div class="mw-heading mw-heading3"><h3 id="Fractional_stops">Fractional stops</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=3" title="Edit section: Fractional stops"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1237032888/mw-parser-output/.tmulti">.mw-parser-output .tmulti .multiimageinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .tsingle .thumbcaption{text-align:left}.mw-parser-output .tmulti .trow>.thumbcaption{text-align:center}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmulti .multiimageinner img{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmulti .multiimageinner img{background-color:white}}</style><div class="thumb tmulti tright"><div class="thumbinner multiimageinner" style="width:248px;max-width:248px"><div class="trow"><div class="tsingle" style="width:122px;max-width:122px"><div class="thumbimage"><span typeof="mw:File"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Povray_focal_blur_animation.gif" class="mw-file-description"><img alt="Changing a camera's aperture in half-stops" src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Povray_focal_blur_animation.gif/120px-Povray_focal_blur_animation.gif" decoding="async" width="120" height="90" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Povray_focal_blur_animation.gif/180px-Povray_focal_blur_animation.gif 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Povray_focal_blur_animation.gif/240px-Povray_focal_blur_animation.gif 2x" data-file-width="512" data-file-height="384"/></a></span></div></div><div class="tsingle" style="width:122px;max-width:122px"><div class="thumbimage"><span typeof="mw:File"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Povray_focal_blur_animation_mode_tan.gif" class="mw-file-description"><img alt="Changing a camera's aperture from zero to infinity" src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Povray_focal_blur_animation_mode_tan.gif/120px-Povray_focal_blur_animation_mode_tan.gif" decoding="async" width="120" height="90" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Povray_focal_blur_animation_mode_tan.gif/180px-Povray_focal_blur_animation_mode_tan.gif 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Povray_focal_blur_animation_mode_tan.gif/240px-Povray_focal_blur_animation_mode_tan.gif 2x" data-file-width="512" data-file-height="384"/></a></span></div></div></div><div class="trow" style="display:flex"><div class="thumbcaption">Computer simulation showing the effects of changing a camera's aperture in half-stops (at left) and from zero to infinity (at right)</div></div></div></div> <p>Most twentieth-century cameras had a continuously variable aperture, using an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Iris_diaphragm" class="mw-redirect" title="Iris diaphragm">iris diaphragm</a>, with each full stop marked. Click-stopped aperture came into common use in the 1960s; the aperture scale usually had a click stop at every whole and half stop. </p><p>On modern cameras, especially when aperture is set on the camera body, f-number is often divided more finely than steps of one stop. Steps of one-third stop (<style data-mw-deduplicate="TemplateStyles:r1154941027">.mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span> EV) are the most common, since this matches the ISO system of <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_speed" title="Film speed">film speeds</a>. Half-stop steps are used on some cameras. Usually the full stops are marked, and the intermediate positions click but are not marked. As an example, the aperture that is one-third stop smaller than <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2.8</span> is <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/3.2</span>, two-thirds smaller is <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/3.5</span>, and one whole stop smaller is <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span>. The next few f-stops in this sequence are: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f/4.5,\ f/5,\ f/5.6,\ f/6.3,\ f/7.1,\ f/8,\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>4.5</mn> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>5</mn> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>5.6</mn> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>6.3</mn> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>7.1</mn> <mo>,</mo> <mtext> </mtext> <mi>f</mi> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mn>8</mn> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f/4.5,\ f/5,\ f/5.6,\ f/6.3,\ f/7.1,\ f/8,\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/097247d5e2fe6d13a82a927cbbd8b75c126cf14f" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:41.656ex; height:2.843ex;" alt="{\displaystyle f/4.5,\ f/5,\ f/5.6,\ f/6.3,\ f/7.1,\ f/8,\ \ldots }"></span> </p><p>To calculate the steps in a full stop (1 EV) one could use </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle ({\sqrt {2}})^{0},\ ({\sqrt {2}})^{1},\ ({\sqrt {2}})^{2},\ ({\sqrt {2}})^{3},\ ({\sqrt {2}})^{4},\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>4</mn> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle ({\sqrt {2}})^{0},\ ({\sqrt {2}})^{1},\ ({\sqrt {2}})^{2},\ ({\sqrt {2}})^{3},\ ({\sqrt {2}})^{4},\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/ebb1ba80d09347b1a7b33a9b56940b20804a3eb7" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:40.993ex; height:3.176ex;" alt="{\displaystyle ({\sqrt {2}})^{0},\ ({\sqrt {2}})^{1},\ ({\sqrt {2}})^{2},\ ({\sqrt {2}})^{3},\ ({\sqrt {2}})^{4},\ \ldots }"></span> </p><p>The steps in a half stop (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span> EV) series would be </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle ({\sqrt {2}})^{\frac {0}{2}},\ ({\sqrt {2}})^{\frac {1}{2}},\ ({\sqrt {2}})^{\frac {2}{2}},\ ({\sqrt {2}})^{\frac {3}{2}},\ ({\sqrt {2}})^{\frac {4}{2}},\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>0</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>2</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>3</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mn>2</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle ({\sqrt {2}})^{\frac {0}{2}},\ ({\sqrt {2}})^{\frac {1}{2}},\ ({\sqrt {2}})^{\frac {2}{2}},\ ({\sqrt {2}})^{\frac {3}{2}},\ ({\sqrt {2}})^{\frac {4}{2}},\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/ce538bd3a2e636348599d46b45fb53b43d315515" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:44.4ex; height:4.009ex;" alt="{\displaystyle ({\sqrt {2}})^{\frac {0}{2}},\ ({\sqrt {2}})^{\frac {1}{2}},\ ({\sqrt {2}})^{\frac {2}{2}},\ ({\sqrt {2}})^{\frac {3}{2}},\ ({\sqrt {2}})^{\frac {4}{2}},\ \ldots }"></span> </p><p>The steps in a third stop (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span> EV) series would be </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle ({\sqrt {2}})^{\frac {0}{3}},\ ({\sqrt {2}})^{\frac {1}{3}},\ ({\sqrt {2}})^{\frac {2}{3}},\ ({\sqrt {2}})^{\frac {3}{3}},\ ({\sqrt {2}})^{\frac {4}{3}},\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>0</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>2</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>3</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mn>2</mn> </msqrt> </mrow> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mn>3</mn> </mfrac> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle ({\sqrt {2}})^{\frac {0}{3}},\ ({\sqrt {2}})^{\frac {1}{3}},\ ({\sqrt {2}})^{\frac {2}{3}},\ ({\sqrt {2}})^{\frac {3}{3}},\ ({\sqrt {2}})^{\frac {4}{3}},\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/3fd219a2821d2e332e6228a2986c14cc1fc46641" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:44.4ex; height:4.009ex;" alt="{\displaystyle ({\sqrt {2}})^{\frac {0}{3}},\ ({\sqrt {2}})^{\frac {1}{3}},\ ({\sqrt {2}})^{\frac {2}{3}},\ ({\sqrt {2}})^{\frac {3}{3}},\ ({\sqrt {2}})^{\frac {4}{3}},\ \ldots }"></span> </p><p>As in the earlier DIN and ASA film-speed standards, the ISO speed is defined only in one-third stop increments, and shutter speeds of digital cameras are commonly on the same scale in reciprocal seconds. A portion of the ISO range is the sequence </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \ldots 16/13^{\circ },\ 20/14^{\circ },\ 25/15^{\circ },\ 32/16^{\circ },\ 40/17^{\circ },\ 50/18^{\circ },\ 64/19^{\circ },\ 80/20^{\circ },\ 100/21^{\circ },\ 125/22^{\circ },\ \ldots }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo>…</mo> <mn>16</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>13</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>20</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>14</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>25</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>15</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>32</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>16</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>40</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>17</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>50</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>18</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>64</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>19</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>80</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>20</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>100</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>21</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mn>125</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <msup> <mn>22</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>∘</mo> </mrow> </msup> <mo>,</mo> <mtext> </mtext> <mo>…</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ldots 16/13^{\circ },\ 20/14^{\circ },\ 25/15^{\circ },\ 32/16^{\circ },\ 40/17^{\circ },\ 50/18^{\circ },\ 64/19^{\circ },\ 80/20^{\circ },\ 100/21^{\circ },\ 125/22^{\circ },\ \ldots }</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/082f9935e717c1042b560fb3267f6988cd80cb23" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:93.357ex; height:2.843ex;" alt="{\displaystyle \ldots 16/13^{\circ },\ 20/14^{\circ },\ 25/15^{\circ },\ 32/16^{\circ },\ 40/17^{\circ },\ 50/18^{\circ },\ 64/19^{\circ },\ 80/20^{\circ },\ 100/21^{\circ },\ 125/22^{\circ },\ \ldots }"></span> </p><p>while shutter speeds in reciprocal seconds have a few conventional differences in their numbers (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">15</span></span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">30</span></span>, and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">60</span></span> second instead of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">16</span></span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">32</span></span>, and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">64</span></span>). </p><p>In practice the maximum aperture of a lens is often not an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Integer" title="Integer">integral</a> power of <span class="nowrap">√<span style="border-top:1px solid; padding:0 0.1em;">2</span></span> (i.e., <span class="nowrap">√<span style="border-top:1px solid; padding:0 0.1em;">2</span></span> to the power of a whole number), in which case it is usually a half or third stop above or below an integral power of <span class="nowrap">√<span style="border-top:1px solid; padding:0 0.1em;">2</span></span>. </p><p>Modern electronically controlled interchangeable lenses, such as those used for SLR cameras, have f-stops specified internally in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">8</span></span>-stop increments, so the cameras' <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span>-stop settings are approximated by the nearest <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">8</span></span>-stop setting in the lens.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2021)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading4"><h4 id="Standard_full-stop_f-number_scale">Standard full-stop f-number scale</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=4" title="Edit section: Standard full-stop f-number scale"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Including <a href="/web/20241119105220/https://en.wikipedia.org/wiki/APEX_system" title="APEX system">aperture value</a> AV: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N={\sqrt {2^{\text{AV}}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <msup> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mtext>AV</mtext> </mrow> </msup> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N={\sqrt {2^{\text{AV}}}}}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/50b7a9af47042c2056a94aa78a2c63c080b26356" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:11.346ex; height:3.509ex;" alt="{\displaystyle N={\sqrt {2^{\text{AV}}}}}"></span> </p><p>Conventional and calculated f-numbers, full-stop series: </p> <table class="wikitable" style="text-align:center"> <tbody><tr> <th scope="row">AV </th> <td>−2</td> <td>−1</td> <td>0</td> <td>1</td> <td>2</td> <td>3</td> <td>4</td> <td>5</td> <td>6</td> <td>7</td> <td>8</td> <td>9</td> <td>10</td> <td>11</td> <td>12</td> <td>13</td> <td>14</td> <td>15</td> <td>16 </td></tr> <tr bgcolor="#CCFFCD"> <th scope="row"><i>N</i> </th> <td>0.5</td> <td>0.7</td> <td>1.0</td> <td>1.4</td> <td>2</td> <td>2.8</td> <td>4</td> <td>5.6</td> <td>8</td> <td>11</td> <td>16</td> <td>22</td> <td>32</td> <td>45</td> <td>64</td> <td>90</td> <td>128</td> <td>180</td> <td>256 </td></tr> <tr> <th scope="row">calculated </th> <td>0.5</td> <td>0.707...</td> <td>1.0</td> <td>1.414...</td> <td>2.0</td> <td>2.828...</td> <td>4.0</td> <td>5.657...</td> <td>8.0</td> <td>11.31...</td> <td>16.0</td> <td>22.62...</td> <td>32.0</td> <td>45.25...</td> <td>64.0</td> <td>90.51...</td> <td>128.0</td> <td>181.02...</td> <td>256.0 </td></tr></tbody></table> <div class="mw-heading mw-heading4"><h4 id="Typical_one-half-stop_f-number_scale">Typical one-half-stop f-number scale</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=5" title="Edit section: Typical one-half-stop f-number scale"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable" style="text-align:center"> <tbody><tr> <th scope="row">AV </th> <td>−1</td> <td>−<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>0</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>1</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>2</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>3</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>4</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>5</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>6</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>7</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>8</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>9</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>10</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">10<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>11</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">11<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>12</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">12<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>13</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">13<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td>14 </td></tr> <tr bgcolor="#FFFFCC"> <th scope="row"><i>N</i> </th> <td style="background:#CCFFCC;">0.7</td> <td>0.8</td> <td style="background:#CCFFCC;">1.0</td> <td>1.2</td> <td style="background:#CCFFCC;">1.4</td> <td>1.7</td> <td style="background:#CCFFCC;">2</td> <td>2.4</td> <td style="background:#CCFFCC;">2.8</td> <td>3.3</td> <td style="background:#CCFFCC;">4</td> <td>4.8</td> <td style="background:#CCFFCC;">5.6</td> <td>6.7</td> <td style="background:#CCFFCC;">8</td> <td>9.5</td> <td style="background:#CCFFCC;">11</td> <td>13</td> <td style="background:#CCFFCC;">16</td> <td>19</td> <td style="background:#CCFFCC;">22</td> <td>27</td> <td style="background:#CCFFCC;">32</td> <td>38</td> <td style="background:#CCFFCC;">45</td> <td>54</td> <td style="background:#CCFFCC;">64</td> <td>76</td> <td style="background:#CCFFCC;">90</td> <td>107</td> <td style="background:#CCFFCC;">128 </td></tr></tbody></table> <div class="mw-heading mw-heading4"><h4 id="Typical_one-third-stop_f-number_scale">Typical one-third-stop f-number scale</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=6" title="Edit section: Typical one-third-stop f-number scale"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable" style="text-align:center"> <tbody><tr> <th scope="row">AV </th> <td>−1</td> <td>−<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>−<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span></td> <td>0</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>1</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>2</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>3</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>4</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>5</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>6</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>7</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>8</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>9</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>10</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">10<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">10<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>11</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">11<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">11<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>12</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">12<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">3</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">12<span class="sr-only">+</span><span class="num">2</span>⁄<span class="den">3</span></span></td> <td>13 </td></tr> <tr bgcolor="#e5d1cb"> <th scope="row"><i>N</i> </th> <td style="background:#CCFFCC;">0.7</td> <td>0.8</td> <td>0.9</td> <td style="background:#CCFFCC;">1.0</td> <td>1.1</td> <td>1.2</td> <td style="background:#CCFFCC;">1.4</td> <td>1.6</td> <td>1.8</td> <td style="background:#CCFFCC;">2</td> <td>2.2</td> <td>2.5</td> <td style="background:#CCFFCC;">2.8</td> <td>3.2</td> <td>3.5</td> <td style="background:#CCFFCC;">4</td> <td>4.5</td> <td>5.0</td> <td style="background:#CCFFCC;">5.6</td> <td>6.3</td> <td>7.1</td> <td style="background:#CCFFCC;">8</td> <td>9</td> <td>10</td> <td style="background:#CCFFCC;">11</td> <td>13</td> <td>14</td> <td style="background:#CCFFCC;">16</td> <td>18</td> <td>20</td> <td style="background:#CCFFCC;">22</td> <td>25</td> <td>29</td> <td style="background:#CCFFCC;">32</td> <td>36</td> <td>40</td> <td style="background:#CCFFCC;">45</td> <td>51</td> <td>57</td> <td style="background:#CCFFCC;">64</td> <td>72</td> <td>80</td> <td style="background:#CCFFCC;">90 </td></tr></tbody></table> <p>Sometimes the same number is included on several scales; for example, an aperture of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1.2</span> may be used in either a half-stop<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> or a one-third-stop system;<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> sometimes <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1.3</span> and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/3.2</span> and other differences are used for the one-third stop scale.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Typical_one-quarter-stop_f-number_scale">Typical one-quarter-stop f-number scale</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=7" title="Edit section: Typical one-quarter-stop f-number scale"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable" style="text-align:center"> <tbody><tr> <th scope="row">AV </th> <td>0</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>1</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">1<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>2</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">2<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>3</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">3<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>4</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">4<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>5 </td></tr> <tr bgcolor="#5D8AA8"> <th scope="row"><i>N</i> </th> <td style="background:#CCFFCC;">1.0</td> <td>1.1</td> <td style="background:#FFFFCC;">1.2</td> <td>1.3</td> <td style="background:#CCFFCC;">1.4</td> <td>1.5</td> <td style="background:#FFFFCC;">1.7</td> <td>1.8</td> <td style="background:#CCFFCC;">2</td> <td>2.2</td> <td style="background:#FFFFCC;">2.4</td> <td>2.6</td> <td style="background:#CCFFCC;">2.8</td> <td>3.1</td> <td style="background:#FFFFCC;">3.3</td> <td>3.7</td> <td style="background:#CCFFCC;">4</td> <td>4.4</td> <td style="background:#FFFFCC;">4.8</td> <td>5.2</td> <td style="background:#CCFFCC;">5.6 </td></tr></tbody></table> <table class="wikitable" style="text-align:center"> <tbody><tr> <th scope="row">AV </th> <td>5</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">5<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>6</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">6<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>7</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">7<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>8</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">8<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>9</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">4</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac">9<span class="sr-only">+</span><span class="num">3</span>⁄<span class="den">4</span></span></td> <td>10 </td></tr> <tr bgcolor="#5D8AA8"> <th scope="row"><i>N</i> </th> <td style="background:#CCFFCC;">5.6</td> <td>6.2</td> <td style="background:#FFFFCC;">6.7</td> <td>7.3</td> <td style="background:#CCFFCC;">8</td> <td>8.7</td> <td style="background:#FFFFCC;">9.5</td> <td>10</td> <td style="background:#CCFFCC;">11</td> <td>12</td> <td style="background:#FFFFCC;">14</td> <td>15</td> <td style="background:#CCFFCC;">16</td> <td>17</td> <td style="background:#FFFFCC;">19</td> <td>21</td> <td style="background:#CCFFCC;">22</td> <td>25</td> <td style="background:#FFFFCC;">27</td> <td>29</td> <td style="background:#CCFFCC;">32 </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id="H-stop">H-stop</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=8" title="Edit section: H-stop"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An <b>H-stop</b> (for hole, by convention written with capital letter H) is an f-number equivalent for effective exposure based on the area covered by the holes in the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diffusion_disc" class="mw-redirect" title="Diffusion disc">diffusion discs</a> or <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sieve_aperture" class="mw-redirect" title="Sieve aperture">sieve aperture</a> found in <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Rodenstock_Imagon" title="Rodenstock Imagon">Rodenstock Imagon</a> lenses. </p> <div class="mw-heading mw-heading3"><h3 id="T-stop">T-stop</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=9" title="Edit section: T-stop"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A <b>T-stop</b> (for transmission stops, by convention written with capital letter T) is an f-number adjusted to account for light transmission efficiency (<i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Transmittance" title="Transmittance">transmittance</a></i>). A lens with a T-stop of <span class="texhtml mvar" style="font-style:italic;">N</span> projects an image of the same brightness as an ideal lens with 100% transmittance and an f-number of <span class="texhtml mvar" style="font-style:italic;">N</span>. A particular lens's T-stop, <span class="texhtml mvar" style="font-style:italic;">T</span>, is given by dividing the f-number by the square root of the transmittance of that lens: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle T={\frac {N}{\sqrt {\text{transmittance}}}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>T</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>N</mi> <msqrt> <mtext>transmittance</mtext> </msqrt> </mfrac> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle T={\frac {N}{\sqrt {\text{transmittance}}}}.}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/00019bc9b6d403bb7254c8d787b62e27f40263c4" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.838ex; width:22.253ex; height:6.176ex;" alt="{\displaystyle T={\frac {N}{\sqrt {\text{transmittance}}}}.}"></span> For example, an <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2.0</span> lens with transmittance of 75% has a T-stop of 2.3: <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle T={\frac {2.0}{\sqrt {0.75}}}=2.309...}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>T</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>2.0</mn> <msqrt> <mn>0.75</mn> </msqrt> </mfrac> </mrow> <mo>=</mo> <mn>2.309...</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle T={\frac {2.0}{\sqrt {0.75}}}=2.309...}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/c8ba69ffa38ca312ec95f5a5ebee2094b3e0d29e" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.838ex; width:21.977ex; height:6.176ex;" alt="{\displaystyle T={\frac {2.0}{\sqrt {0.75}}}=2.309...}"></span> Since real lenses have transmittances of less than 100%, a lens's T-stop number is always greater than its f-number.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p><p>With 8% loss per air-glass surface on lenses without coating, <a href="/web/20241119105220/https://en.wikipedia.org/wiki/History_of_photographic_lens_design#Anti-reflection_coating" title="History of photographic lens design">multicoating</a> of lenses is the key in lens design to decrease transmittance losses of lenses. Some reviews of lenses do measure the T-stop or transmission rate in their benchmarks.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> T-stops are sometimes used instead of f-numbers to more accurately determine exposure, particularly when using external <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Light_meter" title="Light meter">light meters</a>.<sup id="cite_ref-KMPCF_13-0" class="reference"><a href="#cite_note-KMPCF-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> Lens transmittances of 60%–95% are typical.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> T-stops are often used in cinematography, where many images are seen in rapid succession and even small changes in exposure will be noticeable. Cinema camera lenses are typically calibrated in T-stops instead of f-numbers.<sup id="cite_ref-KMPCF_13-1" class="reference"><a href="#cite_note-KMPCF-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> In still photography, without the need for rigorous consistency of all lenses and cameras used, slight differences in exposure are less important; however, T-stops are still used in some kinds of special-purpose lenses such as <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Smooth_Trans_Focus" title="Smooth Trans Focus">Smooth Trans Focus</a> lenses by <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Minolta" title="Minolta">Minolta</a> and <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sony" title="Sony">Sony</a>. </p> <div class="mw-heading mw-heading3"><h3 id="ASA/ISO_numbers"><span id="ASA.2FISO_numbers"></span>ASA/ISO numbers</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=10" title="Edit section: ASA/ISO numbers"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_film" title="Photographic film">Photographic film</a>'s and electronic camera sensor's <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photosensitivity" title="Photosensitivity">sensitivity to light</a> is often specified using <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_speed" title="Film speed">ASA/ISO numbers</a>. Both systems have a linear number where a doubling of sensitivity is represented by a doubling of the number, and a logarithmic number. In the ISO system, a 3° increase in the logarithmic number corresponds to a doubling of sensitivity. Doubling or halving the sensitivity is equal to a difference of one T-stop in terms of light transmittance. </p> <div class="mw-heading mw-heading3"><h3 id="Gain">Gain</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=11" title="Edit section: Gain"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Panasonic_Iris-Gain_relationship.png" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/0/09/Panasonic_Iris-Gain_relationship.png/300px-Panasonic_Iris-Gain_relationship.png" decoding="async" width="300" height="35" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/0/09/Panasonic_Iris-Gain_relationship.png/450px-Panasonic_Iris-Gain_relationship.png 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/0/09/Panasonic_Iris-Gain_relationship.png/600px-Panasonic_Iris-Gain_relationship.png 2x" data-file-width="919" data-file-height="108"/></a><figcaption>Iris/Gain relationship on Panasonic camcorders as described in the HC-V785 operating manual</figcaption></figure> <p>Most electronic cameras allow to amplify the signal coming from the pickup element. This amplification is usually called <b><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Gain_(electronics)" title="Gain (electronics)">gain</a></b> and is measured in decibels. Every <span class="nowrap"><span data-sort-value="7000600000000000000♠"></span>6 dB</span> of gain is equivalent to one T-stop in terms of light transmittance. Many camcorders have a unified control over the lens f-number and gain. In this case, starting from zero gain and fully open iris, one can either increase f-number by reducing the iris size while gain remains zero, or one can increase gain while iris remains fully open. </p> <div class="mw-heading mw-heading3"><h3 id="Sunny_16_rule">Sunny 16 rule</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=12" title="Edit section: Sunny 16 rule"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An example of the use of f-numbers in photography is the <i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sunny_16_rule" title="Sunny 16 rule">sunny 16 rule</a></i>: an approximately correct exposure will be obtained on a sunny day by using an aperture of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/16</span> and the shutter speed closest to the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Multiplicative_inverse" title="Multiplicative inverse">reciprocal</a> of the ISO speed of the film; for example, using ISO 200 film, an aperture of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/16</span> and a shutter speed of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">200</span></span> second. The f-number may then be adjusted downwards for situations with lower light. Selecting a lower f-number is "opening up" the lens. Selecting a higher f-number is "closing" or "stopping down" the lens. </p> <div class="mw-heading mw-heading2"><h2 id="Effects_on_image_sharpness">Effects on image sharpness</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=13" title="Edit section: Effects on image sharpness"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Jonquil_flowers_merged.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Jonquil_flowers_merged.jpg/400px-Jonquil_flowers_merged.jpg" decoding="async" width="400" height="264" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Jonquil_flowers_merged.jpg/600px-Jonquil_flowers_merged.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Jonquil_flowers_merged.jpg/800px-Jonquil_flowers_merged.jpg 2x" data-file-width="1600" data-file-height="1054"/></a><figcaption>Comparison of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/32</span> (top-left half) and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/5</span> (bottom-right half)</figcaption></figure> <figure typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Blumen_im_Sommer.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Blumen_im_Sommer.jpg/400px-Blumen_im_Sommer.jpg" decoding="async" width="400" height="77" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Blumen_im_Sommer.jpg/600px-Blumen_im_Sommer.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f2/Blumen_im_Sommer.jpg/800px-Blumen_im_Sommer.jpg 2x" data-file-width="5616" data-file-height="1080"/></a><figcaption>Shallow focus with a wide open lens</figcaption></figure> <p><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_field" title="Depth of field">Depth of field</a> increases with f-number, as illustrated in the image here. This means that photographs taken with a low f-number (large aperture) will tend to have subjects at one distance in focus, with the rest of the image (nearer and farther elements) out of focus. This is frequently used for <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Nature_photography" title="Nature photography">nature photography</a> and <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Portrait_photography" title="Portrait photography">portraiture</a> because background blur (the aesthetic quality known as '<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Bokeh" title="Bokeh">bokeh</a>') can be aesthetically pleasing and puts the viewer's focus on the main subject in the foreground. The <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_field" title="Depth of field">depth of field</a> of an image produced at a given f-number is dependent on other parameters as well, including the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">focal length</a>, the subject distance, and the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_format" title="Film format">format</a> of the film or sensor used to capture the image. Depth of field can be described as depending on just angle of view, subject distance, and <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Entrance_pupil" title="Entrance pupil">entrance pupil</a> diameter (as in <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Moritz_von_Rohr" title="Moritz von Rohr">von Rohr's method</a>). As a result, smaller formats will have a deeper field than larger formats at the same f-number for the same distance of focus and same <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Angle_of_view" class="mw-redirect" title="Angle of view">angle of view</a> since a smaller format requires a shorter focal length (wider angle lens) to produce the same angle of view, and depth of field increases with shorter focal lengths. Therefore, reduced–depth-of-field effects will require smaller f-numbers (and thus potentially more difficult or complex optics) when using small-format cameras than when using larger-format cameras. </p><p>Beyond focus, image sharpness is related to f-number through two different optical effects: <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Optical_aberration" title="Optical aberration">aberration</a>, due to imperfect lens design, and <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diffraction" title="Diffraction">diffraction</a> which is due to the wave nature of light.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> The blur-optimal f-stop varies with the lens design. For modern standard lenses having 6 or 7 elements, the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sharpness_(visual)" class="mw-redirect" title="Sharpness (visual)">sharpest</a> image is often obtained around <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/5.6</span>–<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span>, while for older standard lenses having only 4 elements (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zeiss_Tessar" class="mw-redirect" title="Zeiss Tessar">Tessar formula</a>) stopping to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/11</span> will give the sharpest image.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (July 2015)">citation needed</span></a></i>]</sup> The larger number of elements in modern lenses allow the designer to compensate for aberrations, allowing the lens to give better pictures at lower f-numbers. At small apertures, depth of field and aberrations are improved, but <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diffraction" title="Diffraction">diffraction</a> creates more spreading of the light, causing blur. </p><p>Light falloff is also sensitive to f-stop. Many wide-angle lenses will show a significant light falloff (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Vignetting" title="Vignetting">vignetting</a>) at the edges for large apertures. </p><p><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photojournalist" class="mw-redirect" title="Photojournalist">Photojournalists</a> have a saying, "<a href="/web/20241119105220/https://en.wikipedia.org/wiki/F/8_and_be_there" title="F/8 and be there"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span> and be there</a>", meaning that being on the scene is more important than worrying about technical details. Practically, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span> (in 35 mm and larger formats) allows adequate depth of field and sufficient lens speed for a decent base exposure in most daylight situations.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Human_eye">Human eye</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=14" title="Edit section: Human eye"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Pupillary_light_reflex.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Pupillary_light_reflex.jpg/382px-Pupillary_light_reflex.jpg" decoding="async" width="382" height="127" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Pupillary_light_reflex.jpg/573px-Pupillary_light_reflex.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Pupillary_light_reflex.jpg/764px-Pupillary_light_reflex.jpg 2x" data-file-width="1800" data-file-height="600"/></a><figcaption>The human pupil in its constricted (3 mm) and fully dilated (9 mm) states. At 9 mm, the effective f-number is approximately <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1.6</span>.</figcaption></figure> <p>Computing the f-number of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Human_eye" title="Human eye">human eye</a> involves computing the physical aperture and focal length of the eye. Typically, the pupil can dilate to be as large as 6–7 mm in darkness, which translates into the maximal physical aperture. Some individuals' pupils can dilate to over 9 mm wide. </p><p>The f-number of the human eye varies from about <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8.3</span> in a very brightly lit place to about <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/2.1</span> in the dark.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> Computing the focal length requires that the light-refracting properties of the liquids in the eye be taken into account. Treating the eye as an ordinary air-filled camera and lens results in an incorrect focal length and f-number. </p> <div class="mw-heading mw-heading2"><h2 id="Focal_ratio_in_telescopes"><span class="anchor" id="Focal_ratio"></span>Focal ratio in telescopes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=15" title="Edit section: Focal ratio in telescopes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Focal_ratio.svg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Focal_ratio.svg/250px-Focal_ratio.svg.png" decoding="async" width="250" height="133" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Focal_ratio.svg/375px-Focal_ratio.svg.png 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Focal_ratio.svg/500px-Focal_ratio.svg.png 2x" data-file-width="643" data-file-height="341"/></a><figcaption>Diagram of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_ratio" class="mw-redirect" title="Focal ratio">focal ratio</a> of a simple optical system where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/132e57acb643253e7810ee9702d9581f159a1c61" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.279ex; height:2.509ex;" alt="{\displaystyle f}"></span> is the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">focal length</a> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle D}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>D</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle D}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/f34a0c600395e5d4345287e21fb26efd386990e6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.924ex; height:2.176ex;" alt="{\displaystyle D}"></span> is the diameter of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Objective_(optics)" title="Objective (optics)">objective</a></figcaption></figure> <p>In astronomy, the f-number is commonly referred to as the <i>focal ratio</i> (or <i>f-ratio</i>) notated as <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/f5e3890c981ae85503089652feb48b191b57aae3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.064ex; height:2.176ex;" alt="{\displaystyle N}"></span>. It is still defined as the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">focal length</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle f}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>f</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle f}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/132e57acb643253e7810ee9702d9581f159a1c61" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.279ex; height:2.509ex;" alt="{\displaystyle f}"></span> of an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Objective_(optics)" title="Objective (optics)">objective</a> divided by its diameter <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle D}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>D</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle D}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/f34a0c600395e5d4345287e21fb26efd386990e6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.924ex; height:2.176ex;" alt="{\displaystyle D}"></span> or by the diameter of an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture" title="Aperture">aperture</a> stop in the system: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N={\frac {f}{D}}\quad {\xrightarrow {\times D}}\quad f=ND}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>f</mi> <mi>D</mi> </mfrac> </mrow> <mspace width="1em"/> <mrow class="MJX-TeXAtom-ORD"> <mover> <mo>→</mo> <mpadded width="+0.611em" lspace="0.278em" voffset=".15em"> <mo>×</mo> <mi>D</mi> </mpadded> </mover> </mrow> <mspace width="1em"/> <mi>f</mi> <mo>=</mo> <mi>N</mi> <mi>D</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N={\frac {f}{D}}\quad {\xrightarrow {\times D}}\quad f=ND}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/0526dab2e8782c7a32e292f4f05cd562adcddf61" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:24.895ex; height:5.343ex;" alt="{\displaystyle N={\frac {f}{D}}\quad {\xrightarrow {\times D}}\quad f=ND}"></span> </p><p>Even though the principles of focal ratio are always the same, the application to which the principle is put can differ. In <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography" title="Photography">photography</a> the focal ratio varies the focal-plane illuminance (or optical power per unit area in the image) and is used to control variables such as <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_field" title="Depth of field">depth of field</a>. When using an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Optical_telescope" title="Optical telescope">optical telescope</a> in astronomy, there is no depth of field issue, and the brightness of stellar point sources in terms of total optical power (not divided by area) is a function of absolute aperture area only, independent of focal length. The focal length controls the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Field_of_view#Astronomy" title="Field of view">field of view</a> of the instrument and the scale of the image that is presented at the focal plane to an <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Eyepiece" title="Eyepiece">eyepiece</a>, film plate, or <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Charge-coupled_device" title="Charge-coupled device">CCD</a>. </p><p>For example, the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Southern_Astrophysical_Research_Telescope" title="Southern Astrophysical Research Telescope">SOAR</a> 4-meter telescope has a small field of view (about <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/16</span>) which is useful for stellar studies. The <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Large_Synoptic_Survey_Telescope" class="mw-redirect" title="Large Synoptic Survey Telescope">LSST</a> 8.4 m telescope, which will cover the entire sky every three days, has a very large field of view. Its short 10.3 m focal length (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/1.2</span>) is made possible by an error correction system which includes secondary and tertiary mirrors, a three element refractive system and active mounting and optics.<sup id="cite_ref-RefDesign_18-0" class="reference"><a href="#cite_note-RefDesign-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Camera_equation_(G#)"><span id="Camera_equation_.28G.23.29"></span>Camera equation (G#)</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=16" title="Edit section: Camera equation (G#)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The camera equation, or G#, is the ratio of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Radiance" title="Radiance">radiance</a> reaching the camera sensor to the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Irradiance" title="Irradiance">irradiance</a> on the focal plane of the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera_lens" title="Camera lens">camera lens</a>:<sup id="cite_ref-g-number_19-0" class="reference"><a href="#cite_note-g-number-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle G\#={\frac {1+4N^{2}}{\tau \pi }}\,,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>G</mi> <mi mathvariant="normal">#</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mn>1</mn> <mo>+</mo> <mn>4</mn> <msup> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mrow> <mrow> <mi>τ</mi> <mi>π</mi> </mrow> </mfrac> </mrow> <mspace width="thinmathspace"/> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle G\#={\frac {1+4N^{2}}{\tau \pi }}\,,}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/8db3b338fda85ee2bcbeba6563e414232aec766e" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:17.074ex; height:5.676ex;" alt="{\displaystyle G\#={\frac {1+4N^{2}}{\tau \pi }}\,,}"></span> </p><p>where <span class="texhtml mvar" style="font-style:italic;">τ</span> is the transmission coefficient of the lens, and the units are in inverse <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Steradian" title="Steradian">steradians</a> (sr<sup>−1</sup>). </p> <div class="mw-heading mw-heading2"><h2 id="Working_f-number">Working f-number</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=17" title="Edit section: Working f-number"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The f-number accurately describes the light-gathering ability of a lens only for objects an infinite distance away.<sup id="cite_ref-Greivenkamp_20-0" class="reference"><a href="#cite_note-Greivenkamp-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> This limitation is typically ignored in photography, where f-number is often used regardless of the distance to the object. In <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Optical_design" class="mw-redirect" title="Optical design">optical design</a>, an alternative is often needed for systems where the object is not far from the lens. In these cases the <b>working f-number</b> is used. The working f-number <span class="texhtml mvar" style="font-style:italic;">N<sub>w</sub></span> is given by:<sup id="cite_ref-Greivenkamp_20-1" class="reference"><a href="#cite_note-Greivenkamp-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N_{w}\approx {1 \over 2\mathrm {NA} _{i}}\approx \left(1+{\frac {|m|}{P}}\right)N\,,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>N</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>w</mi> </mrow> </msub> <mo>≈</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mrow> <mn>2</mn> <msub> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">N</mi> <mi mathvariant="normal">A</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi>i</mi> </mrow> </msub> </mrow> </mfrac> </mrow> <mo>≈</mo> <mrow> <mo>(</mo> <mrow> <mn>1</mn> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> </mrow> <mi>P</mi> </mfrac> </mrow> </mrow> <mo>)</mo> </mrow> <mi>N</mi> <mspace width="thinmathspace"/> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N_{w}\approx {1 \over 2\mathrm {NA} _{i}}\approx \left(1+{\frac {|m|}{P}}\right)N\,,}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/d66d162ff02d11d09eceed71542fb5a35fad12bc" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:30.835ex; height:6.343ex;" alt="{\displaystyle N_{w}\approx {1 \over 2\mathrm {NA} _{i}}\approx \left(1+{\frac {|m|}{P}}\right)N\,,}"></span> </p><p>where <span class="texhtml mvar" style="font-style:italic;">N</span> is the uncorrected f-number, <span class="texhtml">NA<sub><i>i</i></sub></span> is the image-space <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Numerical_aperture" title="Numerical aperture">numerical aperture</a> of the lens, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle |m|}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle |m|}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/f9aa0b9c6f0a110ae299bf81e924412842ce2b12" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:3.334ex; height:2.843ex;" alt="{\displaystyle |m|}"></span> is the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Absolute_value" title="Absolute value">absolute value</a> of the lens's <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Magnification" title="Magnification">magnification</a> for an object a particular distance away, and <span class="texhtml mvar" style="font-style:italic;">P</span> is the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pupil_magnification" title="Pupil magnification">pupil magnification</a>. Since the pupil magnification is seldom known it is often assumed to be 1, which is the correct value for all symmetric lenses. </p><p>In photography this means that as one focuses closer, the lens's effective aperture becomes smaller, making the exposure darker. The working f-number is often described in photography as the f-number corrected for lens extensions by a <a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=Bellows_factor&action=edit&redlink=1" class="new" title="Bellows factor (page does not exist)">bellows factor</a>. This is of particular importance in <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Macro_photography" title="Macro photography">macro photography</a>. </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=18" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The system of f-numbers for specifying relative apertures evolved in the late nineteenth century, in competition with several other systems of aperture notation. </p> <div class="mw-heading mw-heading3"><h3 id="Origins_of_relative_aperture">Origins of relative aperture</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=19" title="Edit section: Origins of relative aperture"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1867, Sutton and Dawson defined "apertal ratio" as essentially the reciprocal of the modern f-number. In the following quote, an "apertal ratio" of "<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">24</span></span>" is calculated as the ratio of 6 inches (150 mm) to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">4</span></span> inch (6.4 mm), corresponding to an <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/24</span> f-stop: </p> <blockquote><p>In every lens there is, corresponding to a given apertal ratio (that is, the ratio of the diameter of the stop to the focal length), a certain distance of a near object from it, between which and infinity all objects are in equally good focus. For instance, in a single view lens of 6-inch focus, with a <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">4</span></span> in. stop (apertal ratio one-twenty-fourth), all objects situated at distances lying between 20 feet from the lens and an infinite distance from it (a fixed star, for instance) are in equally good focus. Twenty feet is therefore called the 'focal range' of the lens when this stop is used. The focal range is consequently the distance of the nearest object, which will be in good focus when the ground glass is adjusted for an extremely distant object. In the same lens, the focal range will depend upon the size of the diaphragm used, while in different lenses having the same apertal ratio the focal ranges will be greater as the focal length of the lens is increased. The terms 'apertal ratio' and 'focal range' have not come into general use, but it is very desirable that they should, in order to prevent ambiguity and circumlocution when treating of the properties of photographic lenses.<sup id="cite_ref-Sutton_21-0" class="reference"><a href="#cite_note-Sutton-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup></p></blockquote> <p>In 1874, <a href="/web/20241119105220/https://en.wikipedia.org/wiki/John_Henry_Dallmeyer" title="John Henry Dallmeyer">John Henry Dallmeyer</a> called the ratio <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1/N}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>1</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>/</mo> </mrow> <mi>N</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 1/N}</annotation> </semantics> </math></span><img src="https://web.archive.org/web/20241119105220im_/https://wikimedia.org/api/rest_v1/media/math/render/svg/aa5c2544725c51dfe75eea07ee1f487feb8664c4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:4.389ex; height:2.843ex;" alt="{\displaystyle 1/N}"></span> the "intensity ratio" of a lens: </p> <blockquote><p>The <i>rapidity</i> of a lens depends upon the relation or ratio of the aperture to the equivalent focus. To ascertain this, divide the <i>equivalent focus</i> by the diameter of the actual <i>working aperture</i> of the lens in question; and note down the quotient as the denominator with 1, or unity, for the numerator. Thus to find the ratio of a lens of 2 inches diameter and 6 inches focus, divide the focus by the aperture, or 6 divided by 2 equals 3; i.e., <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">3</span></span> is the intensity ratio.<sup id="cite_ref-Dallmeyer_22-0" class="reference"><a href="#cite_note-Dallmeyer-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup></p></blockquote> <p>Although he did not yet have access to <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Ernst_Abbe" title="Ernst Abbe">Ernst Abbe</a>'s theory of stops and pupils,<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> which was made widely available by <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Siegfried_Czapski" title="Siegfried Czapski">Siegfried Czapski</a> in 1893,<sup id="cite_ref-Czapski_24-0" class="reference"><a href="#cite_note-Czapski-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> Dallmeyer knew that his <i>working aperture</i> was not the same as the physical diameter of the aperture stop: </p> <blockquote><p>It must be observed, however, that in order to find the real <i>intensity ratio</i>, the diameter of the actual working aperture must be ascertained. This is easily accomplished in the case of single lenses, or for double combination lenses used with the full opening, these merely requiring the application of a pair of compasses or rule; but when double or triple-combination lenses are used, with stops inserted <i>between</i> the combinations, it is somewhat more troublesome; for it is obvious that in this case the diameter of the stop employed is not the measure of the actual pencil of light transmitted by the front combination. To ascertain this, focus for a distant object, remove the focusing screen and replace it by the collodion slide, having previously inserted a piece of cardboard in place of the prepared plate. Make a small round hole in the centre of the cardboard with a piercer, and now remove to a darkened room; apply a candle close to the hole, and observe the illuminated patch visible upon the front combination; the diameter of this circle, carefully measured, is the actual working aperture of the lens in question for the particular stop employed.<sup id="cite_ref-Dallmeyer_22-1" class="reference"><a href="#cite_note-Dallmeyer-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup></p></blockquote> <p>This point is further emphasized by Czapski in 1893.<sup id="cite_ref-Czapski_24-1" class="reference"><a href="#cite_note-Czapski-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> According to an English review of his book, in 1894, "The necessity of clearly distinguishing between effective aperture and diameter of physical stop is strongly insisted upon."<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> </p><p>J. H. Dallmeyer's son, <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Thomas_Rudolphus_Dallmeyer" title="Thomas Rudolphus Dallmeyer">Thomas Rudolphus Dallmeyer</a>, inventor of the telephoto lens, followed the <i>intensity ratio</i> terminology in 1899.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Aperture_numbering_systems">Aperture numbering systems</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=20" title="Edit section: Aperture numbering systems"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:No1-A_Autographic_Kodak_Jr.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/No1-A_Autographic_Kodak_Jr.jpg/220px-No1-A_Autographic_Kodak_Jr.jpg" decoding="async" width="220" height="352" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/No1-A_Autographic_Kodak_Jr.jpg/330px-No1-A_Autographic_Kodak_Jr.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/No1-A_Autographic_Kodak_Jr.jpg/440px-No1-A_Autographic_Kodak_Jr.jpg 2x" data-file-width="800" data-file-height="1279"/></a><figcaption> A 1922 Kodak with aperture marked in U.S. stops. An f-number conversion chart has been added by the user.</figcaption></figure> <p>At the same time, there were a number of aperture numbering systems designed with the goal of making exposure times vary in direct or inverse proportion with the aperture, rather than with the square of the f-number or inverse square of the apertal ratio or intensity ratio. But these systems all involved some arbitrary constant, as opposed to the simple ratio of focal length and diameter. </p><p>For example, the <i>Uniform System</i> (U.S.) of apertures was adopted as a standard by the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Royal_Photographic_Society" title="Royal Photographic Society">Photographic Society of Great Britain</a> in the 1880s. Bothamley in 1891 said "The stops of all the best makers are now arranged according to this system."<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> U.S. 16 is the same aperture as <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/16</span>, but apertures that are larger or smaller by a full stop use doubling or halving of the U.S. number, for example <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/11</span> is U.S. 8 and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span> is U.S. 4. The exposure time required is directly proportional to the U.S. number. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Eastman_Kodak" class="mw-redirect" title="Eastman Kodak">Eastman Kodak</a> used U.S. stops on many of their cameras at least in the 1920s. </p><p>By 1895, Hodges contradicts Bothamley, saying that the f-number system has taken over: "This is called the <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/<i>x</i></span> system, and the diaphragms of all modern lenses of good construction are so marked."<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p><p>Here is the situation as seen in 1899: </p> <figure class="mw-halign-center" typeof="mw:File"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Diaphragm_Numbers.gif" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/5/55/Diaphragm_Numbers.gif/823px-Diaphragm_Numbers.gif" decoding="async" width="823" height="477" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/5/55/Diaphragm_Numbers.gif/1235px-Diaphragm_Numbers.gif 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/5/55/Diaphragm_Numbers.gif 2x" data-file-width="1646" data-file-height="954"/></a><figcaption></figcaption></figure> <p>Piper in 1901<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> discusses five different systems of aperture marking: the old and new <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Carl_Zeiss" title="Carl Zeiss">Zeiss</a> systems based on actual intensity (proportional to reciprocal square of the f-number); and the U.S., C.I., and Dallmeyer systems based on exposure (proportional to square of the f-number). He calls the f-number the "ratio number", "aperture ratio number", and "ratio aperture". He calls expressions like <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span> the "fractional diameter" of the aperture, even though it is literally equal to the "absolute diameter" which he distinguishes as a different term. He also sometimes uses expressions like "an aperture of f 8" without the division indicated by the slash. </p><p>Beck and Andrews in 1902 talk about the Royal Photographic Society standard of <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/4</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/5.6</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/8</span>, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1207775266"><span class="fnumber-fallback"><span class="first-letter">f</span>/11.3</span>, etc.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> The R.P.S. had changed their name and moved off of the U.S. system some time between 1895 and 1902. </p> <div class="mw-heading mw-heading3"><h3 id="Typographical_standardization">Typographical standardization</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=21" title="Edit section: Typographical standardization"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Yashica-D_front.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Yashica-D_front.jpg/220px-Yashica-D_front.jpg" decoding="async" width="220" height="340" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Yashica-D_front.jpg/330px-Yashica-D_front.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Yashica-D_front.jpg/440px-Yashica-D_front.jpg 2x" data-file-width="1297" data-file-height="2003"/></a><figcaption><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Yashica#TLRs" title="Yashica">Yashica-D TLR</a> camera front view. This is one of the few cameras that actually says "F-NUMBER" on it.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/File:Yashica-D_top.jpg" class="mw-file-description"><img src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Yashica-D_top.jpg/220px-Yashica-D_top.jpg" decoding="async" width="220" height="136" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Yashica-D_top.jpg/330px-Yashica-D_top.jpg 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Yashica-D_top.jpg/440px-Yashica-D_top.jpg 2x" data-file-width="1396" data-file-height="862"/></a><figcaption>From the top, the Yashica-D's aperture setting window uses the "f:" notation. The aperture is continuously variable with no "stops".</figcaption></figure> <p>By 1920, the term <i>f-number</i> appeared in books both as <i>F number</i> and <i>f/number</i>. In modern publications, the forms <i>f-number</i> and <i>f number</i> are more common, though the earlier forms, as well as <i>F-number</i> are still found in a few books; not uncommonly, the initial lower-case <i>f</i> in <i>f-number</i> or <i>f/number</i> is set in a hooked italic form: ƒ.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p><p>Notations for f-numbers were also quite variable in the early part of the twentieth century. They were sometimes written with a capital F,<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> sometimes with a dot (period) instead of a slash,<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> and sometimes set as a vertical fraction.<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p><p>The 1961 <a href="/web/20241119105220/https://en.wikipedia.org/wiki/American_National_Standards_Institute" title="American National Standards Institute">ASA</a> standard PH2.12-1961 <i>American Standard General-Purpose Photographic Exposure Meters (Photoelectric Type)</i> specifies that "The symbol for relative apertures shall be ƒ/ or ƒ: followed by the effective ƒ-number." They show the hooked italic 'ƒ' not only in the symbol, but also in the term <i>f-number</i>, which today is more commonly set in an ordinary non-italic face. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=22" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239009302">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output 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src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/25px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="25" height="28" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/37px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/49px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600"/></a></span></span><span class="portalbox-link"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Portal:Physics" 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title="Circle of confusion">Circle of confusion</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Group_f/64" title="Group f/64">Group f/64</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_lens_design" title="Photographic lens design">Photographic lens design</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pinhole_camera" title="Pinhole camera">Pinhole camera</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Preferred_number" title="Preferred number">Preferred number</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=23" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-ReferenceA-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-ReferenceA_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ReferenceA_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Smith, Warren <i>Modern Optical Engineering</i>, 4th Ed., 2007 McGraw-Hill Professional, p. 183.</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFHecht1987" class="citation book cs1">Hecht, Eugene (1987). <i>Optics</i> (2nd ed.). Addison Wesley. p. 152. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/0-201-11609-X" title="Special:BookSources/0-201-11609-X"><bdi>0-201-11609-X</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Optics&rft.pages=152&rft.edition=2nd&rft.pub=Addison+Wesley&rft.date=1987&rft.isbn=0-201-11609-X&rft.aulast=Hecht&rft.aufirst=Eugene&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreivenkamp2004" class="citation book cs1">Greivenkamp, John E. (2004). <i>Field Guide to Geometrical Optics</i>. SPIE Field Guides vol. FG01. Bellingham, Wash: <a href="/web/20241119105220/https://en.wikipedia.org/wiki/SPIE#SPIE_Press" title="SPIE">SPIE</a>. p. 29. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/9780819452948" title="Special:BookSources/9780819452948"><bdi>9780819452948</bdi></a>. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://search.worldcat.org/oclc/53896720">53896720</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Field+Guide+to+Geometrical+Optics&rft.place=Bellingham%2C+Wash&rft.series=SPIE+Field+Guides+vol.+FG01&rft.pages=29&rft.pub=SPIE&rft.date=2004&rft_id=info%3Aoclcnum%2F53896720&rft.isbn=9780819452948&rft.aulast=Greivenkamp&rft.aufirst=John+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">Smith, Warren <i>Modern Lens Design</i> 2005 McGraw-Hill.</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">ISO, Photography—Apertures and related properties pertaining to photographic lenses—Designations and measurements, ISO 517:2008</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">See <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Area_of_a_circle" title="Area of a circle">Area of a circle</a>.</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHarry_C._Box2003" class="citation book cs1">Harry C. Box (2003). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=YjAzP4i1oFcC&pg=PA136"><i>Set lighting technician's handbook: film lighting equipment, practice, and electrical distribution</i></a> (3rd ed.). Focal Press. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/978-0-240-80495-8" title="Special:BookSources/978-0-240-80495-8"><bdi>978-0-240-80495-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Set+lighting+technician%27s+handbook%3A+film+lighting+equipment%2C+practice%2C+and+electrical+distribution&rft.edition=3rd&rft.pub=Focal+Press&rft.date=2003&rft.isbn=978-0-240-80495-8&rft.au=Harry+C.+Box&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DYjAzP4i1oFcC%26pg%3DPA136&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPaul_Kay2003" class="citation book cs1">Paul Kay (2003). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=DvYMl-s1_9YC&pg=PA19"><i>Underwater photography</i></a>. Guild of Master Craftsman. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/978-1-86108-322-7" title="Special:BookSources/978-1-86108-322-7"><bdi>978-1-86108-322-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Underwater+photography&rft.pub=Guild+of+Master+Craftsman&rft.date=2003&rft.isbn=978-1-86108-322-7&rft.au=Paul+Kay&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DDvYMl-s1_9YC%26pg%3DPA19&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDavid_W._Samuelson1998" class="citation book cs1">David W. Samuelson (1998). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=IWkpoJKM_ucC&pg=PA145"><i>Manual for cinematographers</i></a> (2nd ed.). Focal Press. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/978-0-240-51480-2" title="Special:BookSources/978-0-240-51480-2"><bdi>978-0-240-51480-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Manual+for+cinematographers&rft.edition=2nd&rft.pub=Focal+Press&rft.date=1998&rft.isbn=978-0-240-51480-2&rft.au=David+W.+Samuelson&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DIWkpoJKM_ucC%26pg%3DPA145&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://www.dxomark.com/glossary/transmission-light-transmission/">Transmission, light transmission</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20210508111318/https://www.dxomark.com/glossary/transmission-light-transmission/">Archived</a> 2021-05-08 at the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, DxOMark</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://www.dxomark.com/sigma-85mm-f1-4-art-lens-review-new-benchmark/">Sigma 85mm F1.4 Art lens review: New benchmark</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20180104073126/https://www.dxomark.com/sigma-85mm-f1-4-art-lens-review-new-benchmark/">Archived</a> 2018-01-04 at the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, DxOMark</span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://www.lenstip.com/129.1-article-Colour_rendering_in_binoculars_and_lenses.html">Colour rendering in binoculars and lenses - Colours and transmission</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20180104013937/https://www.lenstip.com/129.1-article-Colour_rendering_in_binoculars_and_lenses.html">Archived</a> 2018-01-04 at the <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, LensTip.com</span> </li> <li id="cite_note-KMPCF-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-KMPCF_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-KMPCF_13-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20021002095739/http://www.kodak.com/US/en/motion/support/h2/intro01P.shtml">"Kodak Motion Picture Camera Films"</a>. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Eastman_Kodak" class="mw-redirect" title="Eastman Kodak">Eastman Kodak</a>. November 2000. Archived from <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/http://www.kodak.com/US/en/motion/support/h2/intro01P.shtml">the original</a> on 2002-10-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2007-09-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Kodak+Motion+Picture+Camera+Films&rft.pub=Eastman+Kodak&rft.date=2000-11&rft_id=http%3A%2F%2Fwww.kodak.com%2FUS%2Fen%2Fmotion%2Fsupport%2Fh2%2Fintro01P.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/http://forums.dpreview.com/forums/post/33785655">"Marianne Oelund, "Lens T-stops", dpreview.com, 2009"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20121110221724/http://forums.dpreview.com/forums/post/33785655">Archived</a> from the original on 2012-11-10<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-01-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Marianne+Oelund%2C+%22Lens+T-stops%22%2C+dpreview.com%2C+2009&rft_id=http%3A%2F%2Fforums.dpreview.com%2Fforums%2Fpost%2F33785655&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichael_John_Langford2000" class="citation book cs1">Michael John Langford (2000). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://archive.org/details/basicphotography00lang"><i>Basic Photography</i></a></span>. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_Press" title="Focal Press">Focal Press</a>. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/0-240-51592-7" title="Special:BookSources/0-240-51592-7"><bdi>0-240-51592-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Basic+Photography&rft.pub=Focal+Press&rft.date=2000&rft.isbn=0-240-51592-7&rft.au=Michael+John+Langford&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fbasicphotography00lang&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLevy2001" class="citation book cs1">Levy, Michael (2001). <i>Selecting and Using Classic Cameras: A User's Guide to Evaluating Features, Condition & Usability of Classic Cameras</i>. Amherst Media, Inc. p. 163. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/978-1-58428-054-5" title="Special:BookSources/978-1-58428-054-5"><bdi>978-1-58428-054-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Selecting+and+Using+Classic+Cameras%3A+A+User%27s+Guide+to+Evaluating+Features%2C+Condition+%26+Usability+of+Classic+Cameras&rft.pages=163&rft.pub=Amherst+Media%2C+Inc&rft.date=2001&rft.isbn=978-1-58428-054-5&rft.aulast=Levy&rft.aufirst=Michael&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHecht1987" class="citation book cs1">Hecht, Eugene (1987). <i>Optics</i> (2nd ed.). <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Addison_Wesley" class="mw-redirect" title="Addison Wesley">Addison Wesley</a>. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/0-201-11609-X" title="Special:BookSources/0-201-11609-X"><bdi>0-201-11609-X</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Optics&rft.edition=2nd&rft.pub=Addison+Wesley&rft.date=1987&rft.isbn=0-201-11609-X&rft.aulast=Hecht&rft.aufirst=Eugene&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span> Sect. 5.7.1</span> </li> <li id="cite_note-RefDesign-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-RefDesign_18-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCharles_F._Claver2007" class="citation journal cs1">Charles F. Claver; et al. (2007-03-19). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://web.archive.org/web/20090306173830/http://lsst.org/files/docs/LSST-RefDesign.pdf">"LSST Reference Design"</a> <span class="cs1-format">(PDF)</span>. LSST Corporation: 45–50. Archived from <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/http://lsst.org/files/docs/LSST-RefDesign.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2009-03-06<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-01-10</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=LSST+Reference+Design&rft.pages=45-50&rft.date=2007-03-19&rft.au=Charles+F.+Claver&rft_id=http%3A%2F%2Flsst.org%2Ffiles%2Fdocs%2FLSST-RefDesign.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span> <span class="cs1-visible-error citation-comment"><code class="cs1-code">{{<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Template:Cite_journal" title="Template:Cite journal">cite journal</a>}}</code>: </span><span class="cs1-visible-error citation-comment">Cite journal requires <code class="cs1-code">|journal=</code> (<a href="/web/20241119105220/https://en.wikipedia.org/wiki/Help:CS1_errors#missing_periodical" title="Help:CS1 errors">help</a>)</span></span> </li> <li id="cite_note-g-number-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-g-number_19-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDriggers2003" class="citation book cs1">Driggers, Ronald G. (2003). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=rcrGlrguj1YC"><i>Encyclopedia of Optical Engineering: Pho-Z, pages 2049-3050</i></a>. CRC Press. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/978-0-8247-4252-2" title="Special:BookSources/978-0-8247-4252-2"><bdi>978-0-8247-4252-2</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2020-06-18</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Encyclopedia+of+Optical+Engineering%3A+Pho-Z%2C+pages+2049-3050&rft.pub=CRC+Press&rft.date=2003&rft.isbn=978-0-8247-4252-2&rft.aulast=Driggers&rft.aufirst=Ronald+G.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DrcrGlrguj1YC&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-Greivenkamp-20"><span class="mw-cite-backlink">^ <a href="#cite_ref-Greivenkamp_20-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Greivenkamp_20-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreivenkamp2004" class="citation book cs1">Greivenkamp, John E. (2004). <i>Field Guide to Geometrical Optics</i>. SPIE Field Guides vol. <b>FG01</b>. SPIE. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/0-8194-5294-7" title="Special:BookSources/0-8194-5294-7"><bdi>0-8194-5294-7</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Field+Guide+to+Geometrical+Optics&rft.pub=SPIE&rft.date=2004&rft.isbn=0-8194-5294-7&rft.aulast=Greivenkamp&rft.aufirst=John+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span> p. 29.</span> </li> <li id="cite_note-Sutton-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-Sutton_21-0">^</a></b></span> <span class="reference-text">Thomas Sutton and George Dawson, <i>A Dictionary of Photography</i>, London: Sampson Low, Son & Marston, 1867, (p. 122).</span> </li> <li id="cite_note-Dallmeyer-22"><span class="mw-cite-backlink">^ <a href="#cite_ref-Dallmeyer_22-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Dallmeyer_22-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">John Henry Dallmeyer, <i>Photographic Lenses: On Their Choice and Use – Special Edition Edited for American Photographers</i>, pamphlet, 1874.</span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSouthall1910" class="citation book cs1">Southall, James P. C. (1910). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://archive.org/details/principlesandme01soutgoog/page/n493"><i>The Principles and Methods of Geometrical Optics: Especially as applied to the theory of optical instruments</i></a>. Macmillan. p. 537.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Principles+and+Methods+of+Geometrical+Optics%3A+Especially+as+applied+to+the+theory+of+optical+instruments&rft.pages=537&rft.pub=Macmillan&rft.date=1910&rft.aulast=Southall&rft.aufirst=James+P.+C.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fprinciplesandme01soutgoog%2Fpage%2Fn493&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-Czapski-24"><span class="mw-cite-backlink">^ <a href="#cite_ref-Czapski_24-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Czapski_24-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Siegfried Czapski, <i>Theorie der optischen Instrumente, nach Abbe,</i> Breslau: Trewendt, 1893.</span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text">Henry Crew, "Theory of Optical Instruments by Dr. Czapski," in <i>Astronomy and Astro-physics</i> XIII pp. 241–243, 1894.</span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text">Thomas R. Dallmeyer, <i>Telephotography: An elementary treatise on the construction and application of the telephotographic lens</i>, London: Heinemann, 1899.</span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text">C. H. Bothamley, <i>Ilford Manual of Photography</i>, London: Britannia Works Co. Ltd., 1891.</span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text">John A. Hodges, <i>Photographic Lenses: How to Choose, and How to Use</i>, Bradford: Percy Lund & Co., 1895.</span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">C. Welborne Piper, <i>A First Book of the Lens: An Elementary Treatise on the Action and Use of the Photographic Lens</i>, London: Hazell, Watson, and Viney, Ltd., 1901.</span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text">Conrad Beck and Herbert Andrews, <i>Photographic Lenses: A Simple Treatise</i>, second edition, London: R. & J. Beck Ltd., c. 1902.</span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?as_q=lens+aperture&num=50&as_epq=f-number">Google search</a></span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIves1920" class="citation book cs1">Ives, Herbert Eugene (1920). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=ypakouuKvwYC&pg=RA2-PA61"><i>Airplane Photography</i></a> <span class="cs1-format">(Google)</span>. Philadelphia: J. B. Lippincott. p. 61. <a href="/web/20241119105220/https://en.wikipedia.org/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Special:BookSources/9780598722225" title="Special:BookSources/9780598722225"><bdi>9780598722225</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2007-03-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Airplane+Photography&rft.place=Philadelphia&rft.pages=61&rft.pub=J.+B.+Lippincott&rft.date=1920&rft.isbn=9780598722225&rft.aulast=Ives&rft.aufirst=Herbert+Eugene&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DypakouuKvwYC%26pg%3DRA2-PA61&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMees1920" class="citation book cs1">Mees, Charles Edward Kenneth (1920). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=V7MCVGREPfkC&q=aperture+lens+uniform-system+date:0-1930"><i>The Fundamentals of Photography</i></a>. Eastman Kodak. p. 28<span class="reference-accessdate">. Retrieved <span class="nowrap">2007-03-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Fundamentals+of+Photography&rft.pages=28&rft.pub=Eastman+Kodak&rft.date=1920&rft.aulast=Mees&rft.aufirst=Charles+Edward+Kenneth&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DV7MCVGREPfkC%26q%3Daperture%2Blens%2Buniform-system%2Bdate%3A0-1930&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDerr1906" class="citation book cs1">Derr, Louis (1906). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20241119105220/https://books.google.com/books?id=AN6d4zTjquwC&pg=PA83"><i>Photography for Students of Physics and Chemistry</i></a> <span class="cs1-format">(Google)</span>. London: Macmillan. p. 83<span class="reference-accessdate">. Retrieved <span class="nowrap">2007-03-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Photography+for+Students+of+Physics+and+Chemistry&rft.place=London&rft.pages=83&rft.pub=Macmillan&rft.date=1906&rft.aulast=Derr&rft.aufirst=Louis&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DAN6d4zTjquwC%26pg%3DPA83&rfr_id=info%3Asid%2Fen.wikipedia.org%3AF-number" class="Z3988"></span></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20241119105220/https://en.wikipedia.org/w/index.php?title=F-number&action=edit&section=24" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid 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href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera" title="Camera">Camera</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Light_field_camera" title="Light field camera">light-field</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_camera" title="Digital camera">digital</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Field_camera" title="Field camera">field</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Instant_camera" title="Instant camera">instant</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera_phone" title="Camera phone">phone</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pinhole_camera" title="Pinhole camera">pinhole</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Press_camera" title="Press camera">press</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Rangefinder_camera" title="Rangefinder camera">rangefinder</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Single-lens_reflex_camera" title="Single-lens reflex camera">SLR</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera" title="Camera">still</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Twin-lens_reflex_camera" title="Twin-lens reflex camera">TLR</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Toy_camera" title="Toy camera">toy</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/View_camera" title="View camera">view</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Darkroom" title="Darkroom">Darkroom</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Enlarger" title="Enlarger">enlarger</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Safelight" title="Safelight">safelight</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_film" title="Photographic film">Film</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_base" title="Film base">base</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_format" title="Film format">format</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_holder" title="Film holder">holder</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_stock" title="Film stock">stock</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photographic_films" title="List of photographic films">available films</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_discontinued_photographic_films" title="List of discontinued photographic films">discontinued films</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_filter" title="Photographic filter">Filter</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Flash_(photography)" title="Flash (photography)">Flash</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Beauty_dish" title="Beauty dish">beauty dish</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Cucoloris" title="Cucoloris">cucoloris</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Gobo_(lighting)" title="Gobo (lighting)">gobo</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Hot_shoe" title="Hot shoe">hot shoe</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lens_hood" title="Lens hood">lens hood</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Monolight" title="Monolight">monolight</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Reflector_(photography)" title="Reflector (photography)">reflector</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Snoot" title="Snoot">snoot</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Softbox" title="Softbox">softbox</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera_lens" title="Camera lens">Lens</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Long-focus_lens" title="Long-focus lens">long-focus</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Prime_lens" title="Prime lens">prime</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zoom_lens" title="Zoom lens">zoom</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wide-angle_lens" title="Wide-angle lens">wide-angle</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fisheye_lens" title="Fisheye lens">fisheye</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Swivel_lens" title="Swivel lens">swivel</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Telephoto_lens" title="Telephoto lens">telephoto</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photographic_equipment_makers" title="List of photographic equipment makers">Manufacturers</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Monopod" title="Monopod">Monopod</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Movie_projector" title="Movie projector">Movie projector</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Slide_projector" title="Slide projector">Slide projector</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Tripod_(photography)" title="Tripod (photography)">Tripod</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Tripod_head" title="Tripod head">head</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zone_plate" title="Zone plate">Zone plate</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Terminology</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/35_mm_equivalent_focal_length" title="35 mm equivalent focal length">35 mm equivalent focal length</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Angle_of_view_(photography)" title="Angle of view (photography)">Angle of view</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aperture" title="Aperture">Aperture</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Backscatter_(photography)" title="Backscatter (photography)">Backscatter</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Black-and-white" title="Black-and-white">Black-and-white</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Chromatic_aberration" title="Chromatic aberration">Chromatic aberration</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Circle_of_confusion" title="Circle of confusion">Circle of confusion</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Clipping_(photography)" title="Clipping (photography)">Clipping</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_balance" title="Color balance">Color balance</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_temperature" title="Color temperature">Color temperature</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_field" title="Depth of field">Depth of field</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Depth_of_focus" title="Depth of focus">Depth of focus</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_(photography)" title="Exposure (photography)">Exposure</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_compensation" title="Exposure compensation">Exposure compensation</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposure_value" title="Exposure value">Exposure value</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zebra_patterning" title="Zebra patterning">Zebra patterning</a></li> <li><a class="mw-selflink selflink">F-number</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_format" title="Film format">Film format</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Large_format" title="Large format">large</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Medium_format" title="Medium format">medium</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_speed" title="Film speed">Film speed</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Focal_length" title="Focal length">Focal length</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Guide_number" title="Guide number">Guide number</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Hyperfocal_distance" title="Hyperfocal distance">Hyperfocal distance</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lens_flare" title="Lens flare">Lens flare</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Metering_mode" title="Metering mode">Metering mode</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Perspective_distortion" title="Perspective distortion">Perspective distortion</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photograph" title="Photograph">Photograph</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_printing" title="Photographic printing">Photographic printing</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Albumen_print" title="Albumen print">Albumen</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photographic_processes" title="List of photographic processes">Photographic processes</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Reciprocity_(photography)" title="Reciprocity (photography)">Reciprocity</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Red-eye_effect" title="Red-eye effect">Red-eye effect</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Science_of_photography" title="Science of photography">Science of photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Shutter_speed" title="Shutter speed">Shutter speed</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Flash_synchronization" title="Flash synchronization">Sync</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zone_System" title="Zone System">Zone System</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Genres</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Abstract_photography" title="Abstract photography">Abstract</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aerial_photography" title="Aerial photography">Aerial</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Aircraft_spotting" title="Aircraft spotting">Aircraft</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Architectural_photography" title="Architectural photography">Architectural</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Astrophotography" title="Astrophotography">Astrophotography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Banquet_photography" title="Banquet photography">Banquet</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Candid_photography" title="Candid photography">Candid</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Conceptual_photography" title="Conceptual photography">Conceptual</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Conservation_photography" title="Conservation photography">Conservation</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Cloudscape_photography" title="Cloudscape photography">Cloudscape</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Documentary_photography" title="Documentary photography">Documentary</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Eclipse_photography" title="Eclipse photography">Eclipse</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Visual_anthropology" title="Visual anthropology">Ethnographic</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Erotic_photography" title="Erotic photography">Erotic</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fashion_photography" title="Fashion photography">Fashion</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fine-art_photography" title="Fine-art photography">Fine-art</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fire_photography" title="Fire photography">Fire</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Forensic_photography" title="Forensic photography">Forensic</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Glamour_photography" title="Glamour photography">Glamour</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/High-speed_photography" title="High-speed photography">High-speed</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Landscape_photography" title="Landscape photography">Landscape</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Monochrome_photography" title="Monochrome photography">Monochrome</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Nature_photography" title="Nature photography">Nature</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Neues_Sehen" title="Neues Sehen">Neues Sehen</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Nude_photography" title="Nude photography">Nude</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photojournalism" title="Photojournalism">Photojournalism</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pictorialism" title="Pictorialism">Pictorialism</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pornography" title="Pornography">Pornography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Portrait_photography" title="Portrait photography">Portrait</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Post-mortem_photography" title="Post-mortem photography">Post-mortem</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Ruins_photography" title="Ruins photography">Ruins</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Selfie" title="Selfie">Selfie</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Space_selfie" title="Space selfie">space selfie</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Social_documentary_photography" title="Social documentary photography">Social documentary</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sports_photography" title="Sports photography">Sports</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Still_life_photography" title="Still life photography">Still life</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Stock_photography" title="Stock photography">Stock</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Straight_photography" title="Straight photography">Straight photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Street_photography" title="Street photography">Street</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Toy_camera" title="Toy camera">Toy camera</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Underwater_photography" title="Underwater photography">Underwater</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Vernacular_photography" title="Vernacular photography">Vernacular</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wedding_photography" title="Wedding photography">Wedding</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Wildlife_photography" title="Wildlife photography">Wildlife</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Techniques</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Afocal_photography" title="Afocal photography">Afocal</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Bokeh" title="Bokeh">Bokeh</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Brenizer_method" title="Brenizer method">Brenizer</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Burst_mode_(photography)" title="Burst mode (photography)">Burst mode</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Contre-jour" title="Contre-jour">Contre-jour</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Exposing_to_the_right" title="Exposing to the right">ETTR</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fill_flash" title="Fill flash">Fill flash</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Fireworks_photography" title="Fireworks photography">Fireworks</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Hand-colouring_of_photographs" title="Hand-colouring of photographs">Hand-colouring</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Harris_shutter" title="Harris shutter">Harris shutter</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/High-speed_photography" title="High-speed photography">High-speed</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Holography" title="Holography">Holography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Infrared_photography" title="Infrared photography">Infrared</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Intentional_camera_movement" title="Intentional camera movement">Intentional camera movement</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Kirlian_photography" title="Kirlian photography">Kirlian</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Kite_aerial_photography" title="Kite aerial photography">Kite aerial</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lo-fi_photography" title="Lo-fi photography">Lo-fi photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Long-exposure_photography" title="Long-exposure photography">Long-exposure</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Luminogram" title="Luminogram">Luminogram</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Macro_photography" title="Macro photography">Macro</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Mordan%C3%A7age" title="Mordançage">Mordançage</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Multiple_exposure" title="Multiple exposure">Multiple exposure</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Multi-exposure_HDR_capture" title="Multi-exposure HDR capture">Multi-exposure HDR capture</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Night_photography" title="Night photography">Night</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Panning_(camera)" title="Panning (camera)">Panning</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Panoramic_photography" title="Panoramic photography">Panoramic</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photogram" title="Photogram">Photogram</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_print_toning" title="Photographic print toning">Print toning</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pigeon_photography" title="Pigeon photography">Pigeon photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Redscale" title="Redscale">Redscale</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Rephotography" title="Rephotography">Rephotography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Rollout_photography" title="Rollout photography">Rollout</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Scanography" title="Scanography">Scanography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Schlieren_photography" title="Schlieren photography">Schlieren photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sabattier_effect" title="Sabattier effect">Sabattier effect</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Slow_motion" title="Slow motion">Slow motion</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Stereoscopy" title="Stereoscopy">Stereoscopy</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Stopping_down" title="Stopping down">Stopping down</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Strip_photography" title="Strip photography">Strip</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Slit-scan_photography" title="Slit-scan photography">Slit-scan</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Sun_printing" title="Sun printing">Sun printing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Tilt%E2%80%93shift_photography" title="Tilt–shift photography">Tilt–shift</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Miniature_faking" title="Miniature faking">Miniature faking</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Time-lapse_photography" title="Time-lapse photography">Time-lapse</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Ultraviolet_photography" title="Ultraviolet photography">Ultraviolet</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Vignetting" title="Vignetting">Vignetting</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Xerox_art" title="Xerox art">Xerography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Zoom_burst" title="Zoom burst">Zoom burst</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Composition_(visual_arts)" title="Composition (visual arts)">Composition</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Diagonal_method" title="Diagonal method">Diagonal method</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Framing_(visual_arts)" title="Framing (visual arts)">Framing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Headroom_(photographic_framing)" title="Headroom (photographic framing)">Headroom</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lead_room" title="Lead room">Lead room</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Rule_of_thirds" title="Rule of thirds">Rule of thirds</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Simplicity_(photography)" title="Simplicity (photography)">Simplicity</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Golden_triangle_(composition)" title="Golden triangle (composition)">Golden triangle (composition)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/History_of_photography" title="History of photography">History</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Timeline_of_photography_technology" title="Timeline of photography technology">Timeline of photography technology</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Ambrotype" title="Ambrotype">Ambrotype</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Analog_photography" title="Analog photography">Analog photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Autochrome_Lumi%C3%A8re" title="Autochrome Lumière">Autochrome Lumière</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Box_camera" title="Box camera">Box camera</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Calotype" title="Calotype">Calotype</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Camera_obscura" title="Camera obscura">Camera obscura</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Daguerreotype" title="Daguerreotype">Daguerreotype</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Dufaycolor" title="Dufaycolor">Dufaycolor</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Heliography" title="Heliography">Heliography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Lippmann_plate" title="Lippmann plate">Lippmann plate</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Painted_photography_backdrops" title="Painted photography backdrops">Painted photography backdrops</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_and_the_law" title="Photography and the law">Photography and the law</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_plate" title="Photographic plate">Glass plate</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Tintype" title="Tintype">Tintype</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Visual_arts" title="Visual arts">Visual arts</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Regional</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Albania" title="Photography in Albania">Albania</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Bangladesh" title="Photography in Bangladesh">Bangladesh</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Canada" title="Photography in Canada">Canada</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_China" title="Photography in China">China</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Denmark" title="Photography in Denmark">Denmark</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Greece" title="Photography in Greece">Greece</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_India" title="Photography in India">India</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Japan" title="Photography in Japan">Japan</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Korea" title="Photography in Korea">Korea</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Luxembourg" title="Photography in Luxembourg">Luxembourg</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Norway" title="Photography in Norway">Norway</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_the_Philippines" title="Photography in the Philippines">Philippines</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Serbia" title="Photography in Serbia">Serbia</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Slovenia" class="mw-redirect" title="Photography in Slovenia">Slovenia</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Sudan" title="Photography in Sudan">Sudan</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Taiwan" title="Photography in Taiwan">Taiwan</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Turkey" title="Photography in Turkey">Turkey</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Ukraine" title="Photography in Ukraine">Ukraine</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_the_United_States" title="Photography in the United States">United States</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Uzbekistan" title="Photography in Uzbekistan">Uzbekistan</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photography_in_Vietnam" title="Photography in Vietnam">Vietnam</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_photography" title="Digital photography">Digital photography</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_camera" title="Digital camera">Digital camera</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_single-lens_reflex_camera" title="Digital single-lens reflex camera">D-SLR</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Comparison_of_digital_SLRs" title="Comparison of digital SLRs">comparison</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Mirrorless_camera" title="Mirrorless camera">MILC</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_camera_back" title="Digital camera back">camera back</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digiscoping" title="Digiscoping">Digiscoping</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Comparison_of_digital_and_film_photography" title="Comparison of digital and film photography">Comparison of digital and film photography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Film_scanner" title="Film scanner">Film scanner</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Image_sensor" title="Image sensor">Image sensor</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Active-pixel_sensor" title="Active-pixel sensor">CMOS APS</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Charge-coupled_device" title="Charge-coupled device">CCD</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Three-CCD_camera" title="Three-CCD camera">Three-CCD camera</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Foveon_X3_sensor" title="Foveon X3 sensor">Foveon X3 sensor</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Image_sharing" title="Image sharing">Image sharing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Pixel" title="Pixel">Pixel</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_photography" title="Color photography">Color photography</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_print_film" title="Color print film">Print film</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Chromogenic_print" title="Chromogenic print">Chromogenic print</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Reversal_film" title="Reversal film">Reversal film</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_management" title="Color management">Color management</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Color_space" title="Color space">color space</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Primary_color" title="Primary color">primary color</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/CMYK_color_model" title="CMYK color model">CMYK color model</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/RGB_color_model" title="RGB color model">RGB color model</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_processing" title="Photographic processing">Photographic<br/>processing</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Bleach_bypass" title="Bleach bypass">Bleach bypass</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/C-41_process" title="C-41 process">C-41 process</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Collodion_process" title="Collodion process">Collodion process</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Cross_processing" title="Cross processing">Cross processing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Cyanotype" title="Cyanotype">Cyanotype</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_developer" title="Photographic developer">Developer</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Digital_image_processing" title="Digital image processing">Digital image processing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Dye_coupler" title="Dye coupler">Dye coupler</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/E-6_process" title="E-6 process">E-6 process</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Photographic_fixer" title="Photographic fixer">Fixer</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Gelatin_silver_process" class="mw-redirect" title="Gelatin silver process">Gelatin silver process</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Gum_printing" title="Gum printing">Gum printing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Instant_film" title="Instant film">Instant film</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/K-14_process" title="K-14 process">K-14 process</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Print_permanence" title="Print permanence">Print permanence</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Push_processing" title="Push processing">Push processing</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Stop_bath" title="Stop bath">Stop bath</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Lists</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_largest_photographs" title="List of largest photographs">Largest photographs</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_most_expensive_photographs" title="List of most expensive photographs">Most expensive photographs</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_museums_devoted_to_one_photographer" title="List of museums devoted to one photographer">Museums devoted to one photographer</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photographs_considered_the_most_important" title="List of photographs considered the most important">Photographs considered the most important</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photographers" title="List of photographers">Photographers</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_Norwegian_photographers" title="List of Norwegian photographers">Norwegian</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_Polish_photographers" title="List of Polish photographers">Polish</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_street_photographers" title="List of street photographers">street</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_women_photographers" title="List of women photographers">women</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/List_of_photography_periodicals" title="List of photography periodicals">Photography periodicals</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Conservation_and_restoration_of_photographs" title="Conservation and restoration of photographs">Conservation and restoration of photographs</a> <ul><li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Conservation_and_restoration_of_film" title="Conservation and restoration of film">film</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Conservation_and_restoration_of_photographic_plates" title="Conservation and restoration of photographic plates">photographic plates</a></li></ul></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Toy_camera#Lomography" title="Toy camera">Lomography</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Polaroid_art" title="Polaroid art">Polaroid art</a></li> <li><a href="/web/20241119105220/https://en.wikipedia.org/wiki/Stereoscopy" title="Stereoscopy">Stereoscopy</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185"/></span></span> <a href="/web/20241119105220/https://en.wikipedia.org/wiki/Category:Photography" title="Category:Photography">Category</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Outline"><img alt="" src="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Global_thinking.svg/10px-Global_thinking.svg.png" decoding="async" width="10" height="16" class="mw-file-element" srcset="//web.archive.org/web/20241119105220im_/https://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Global_thinking.svg/15px-Global_thinking.svg.png 1.5x, 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