{"id":261,"date":"2011-03-30T19:59:26","date_gmt":"2011-03-30T19:59:26","guid":{"rendered":"http:\/\/www.mcfade.co.uk\/blog\/?p=261"},"modified":"2023-07-02T12:23:46","modified_gmt":"2023-07-02T12:23:46","slug":"exposure-explained-via-beer","status":"publish","type":"post","link":"https:\/\/www.mcfade.co.uk\/blog\/exposure-explained-via-beer","title":{"rendered":"Exposure Explained&#8230;. via Beer?"},"content":{"rendered":"<h1>F stops, shutter speeds and ISO can be confusing.<\/h1>\n<p>I like to think in terms of things I understand when trying to explain difficult concepts, and it happens that beer can be roughly equated to exposure&#8230;<\/p>\n<h2>F-Stops<\/h2>\n<p>So the F stop relates to how fast a beer <strong>flows <\/strong>from the pump:-<\/p>\n<ul>\n<li>Guinness takes ages, that&#8217;s got a tiny <strong>flow <\/strong>&#8211; so that&#8217;s a small aperture, like F16, F22 or even F35<\/li>\n<li>Hand pulled bitter comes out really fast &#8211; that&#8217;s like a <a class=\"wpil_keyword_link\" href=\"https:\/\/www.mcfade.co.uk\/blog\/the-unbeatable-benefits-of-using-a-50mm-lens\/%20\" target=\"_blank\" rel=\"noopener\" title=\"The Unbeatable Benefits of Using a 50mm Lens\" data-wpil-keyword-link=\"linked\" data-wpil-monitor-id=\"39299\">fast aperture<\/a>, say F1.4 or F2.8<\/li>\n<li>Lagers and cider are somewhere in the middle, you&#8217;re looking at F5.6-F11 there<\/li>\n<\/ul>\n<h2>Shutter Speed<\/h2>\n<p>Shutter speed relates to <strong>how long<\/strong> it takes to fill your glass<\/p>\n<ul>\n<li>Guinness takes ages so that has a long shutter speed &#8211; maybe 30 seconds<\/li>\n<li>Hand pulled bitter comes out really fast &#8211; so we&#8217;re talking fast shutter speeds, 1\/500th second is pretty fast, though most cameras go to 1\/8000th these days<\/li>\n<li>Lagers and cider are somewhere in the middle, 1 second maybe<\/li>\n<\/ul>\n<h2>The link&#8230;..?<\/h2>\n<p>Can you see how the 2 link&#8230; a slow pouring beer like Guinness takes a long time to fill the glass, whereas a fast hand pulled beer fills the same glass in a fraction of the time. In both cases, you get a full pint, but you just need to vary the <strong>pouring time<\/strong> because of the different <strong>flow <\/strong>of the beer.<\/p>\n<h2>What is ISO?<\/h2>\n<p>What about ISO then&#8230;.<\/p>\n<p>Well this relates to the<strong> size of the glass! <\/strong><\/p>\n<p>It&#8217;s actually the &#8220;speed&#8221; of the film, the sensitivity of your camera&#8217;s sensor, but glass size is easier to think about. It&#8217;s basically how much beer you need to fill the glass.<\/p>\n<p><strong>Lets say ISO 400 = 1 Pint<\/strong><\/p>\n<ul>\n<li>ISO 800 is like a half pint glass &#8211; i.e. it takes HALF AS MUCH BEER to fill it &#8211; it&#8217;s twice as &#8220;fast&#8221;<\/li>\n<li>ISO 200 is like a 2 pint glass (or a litre stein you see in bavaria) &#8211; it takes TWICE AS MUCH BEER to fill it.<\/li>\n<li>ISO 100 would be a 4 pint glass, it takes 4 times as much to fill!<\/li>\n<li>ISO 1600 would be a 1\/4 pint glass &#8211; so it takes a quarter of the beer to fill.<\/li>\n<\/ul>\n<h2>Keeping up&#8230;.?<\/h2>\n<p>So lets gather all this together in camera speak.<\/p>\n<ul>\n<li>We have a &#8220;flow of beer&#8221; = Aperture<\/li>\n<li>We have a &#8220;time the flow runs for&#8221; = Shutter speed<\/li>\n<li>Volume of the glass we&#8217;re pouring in into = ISO<\/li>\n<\/ul>\n<h2>STOPS &#8211; What Are They?<\/h2>\n<p>All these things are\u00a0related closely by a unit called a\u00a0&#8220;<strong>stop<\/strong>&#8221; &#8211; a weird name\u00a0really.<\/p>\n<p>Aperture, ISO and Shutter can all varied by &#8220;stops&#8221;, but they each have different names and &#8220;steps&#8221; between them. The Stops are named as follows:-<\/p>\n<ul>\n<li><strong>Aperture Stops<\/strong> &#8211; F1 F1.4 F2 F2.8 F4 F5.6 F8 F11 F16 F22 etc.<\/li>\n<li><strong>Shutter speed Stops &#8211;\u00a0<\/strong>(units of time, measured in seconds) 1\/1000th 1\/500th 1\/250th 1\/125th 1\/60th 1\/30th etc.<\/li>\n<li><strong>ISO Stops &#8211;\u00a0<\/strong> 50 100 200 400 800 1600 3200<\/li>\n<\/ul>\n<h2>All Doubles and Halves<\/h2>\n<p>The\u00a0Shutter speed and ISO stops\u00a0double or halve when you move along the list. This is because each &#8220;stop&#8221; is &#8220;double or half&#8221; of the neighbour.<\/p>\n<ul>\n<li>1\/500th has neighbours 1\/250th (double the time) and 1\/1000th (half the time)<\/li>\n<li>ISO 400 has ISO 200 or ISO 800 as neighbours.<\/li>\n<\/ul>\n<h2>Aperture Stops Are Strange<\/h2>\n<p>So why does aperture look so odd?<\/p>\n<p>Well its a bit more complex, but each stop is about 1.4 from the neighbours &#8211; so there is a relation ship there. (it&#8217;s to do with the square root of 2 = 1.41).<\/p>\n<p>So from<\/p>\n<ul>\n<li>F1 to F1.4 is 1.4 times &#8211;<\/li>\n<li>next is\u00a0F2 (that&#8217;s 1.4 * 1.4)<\/li>\n<li>next is F2.8 &#8211; (that&#8217;s 1.4 * 2.0)<\/li>\n<li>and so on<\/li>\n<\/ul>\n<h2>So what does all this mean?<\/h2>\n<p>You have 3 variables which control the exposure of a picture &#8211; get them wrong and you&#8217;ll get a badly exposed\u00a0shot. i.e.<\/p>\n<ul>\n<li>if you don&#8217;t let enough light in you get a dark shot \u00a0(or a glass that&#8217;s not full if we talk about beer)<\/li>\n<li>if you let too much light in you get a completely useless white shot \u00a0(or a load of beer flowing over the top of the glass on to the floor)<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>Here&#8217;s the critical thing you need to know &#8211; if you change one of the settings by a &#8220;stop&#8221;, you double (or half) the brightness of the shot.<\/p>\n<p>Yes &#8211; remember, it&#8217;s all doubles and halves<\/p>\n<ul>\n<li>If you increase the shutter speed by 1 stop, the shutter stays open for twice as long and you get exactly twice as much light on the sensor (or twice as much beer in the glass)<\/li>\n<li>If you increase the Aperture by 1 stop, the flow of light is doubled and you get exactly twice as much light on the sensor (or twice as much beer in the glass)<\/li>\n<li>If you increase the ISO by 1 stop, the amount of light needed to get an exposure is\u00a0halved\u00a0and you get an images exactly twice as bright (or you reduce the size of the glass by half &#8211; but the flow of beer is the same, you just may end up with some spillage if you&#8217;re not careful!)<\/li>\n<\/ul>\n<h2>Practice and Learn&#8230;<\/h2>\n<p>Exposure is best learned by using your camera, getting curious and trying various settings &#8211; I&#8217;d recommend putting your camera in <a href=\"https:\/\/www.mcfade.co.uk\/blog\/mastering-manual-mode-a-step-by-step-tutorial-for-new-photographers\/\">Manual exposure mode<\/a> &#8220;M&#8221;, and taking lots of shots and seeing what happens &#8211; go through each Stop in turn and learn that way.<\/p>\n<p>There is a lot more to it than this, but next time you&#8217;re in the pub, watch the beers being poured and think &#8220;exposure&#8221;!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>F stops, shutter speeds and ISO can be confusing. I like to think in terms of things I understand when trying to explain difficult concepts, and it happens that beer can be roughly equated to exposure&#8230; F-Stops So the F stop relates to how fast a beer flows from the pump:- Guinness takes ages, that&#8217;s [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":5706,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"initial","rop_publish_now_accounts":{"twitter_22977785_22977785":"","facebook_10157410341118549_123005067715685":""},"rop_publish_now_history":[],"rop_publish_now_status":"pending","_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ngg_post_thumbnail":0,"footnotes":""},"categories":[3,9,14,10],"tags":[],"class_list":["post-261","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-photography","category-tips","category-workshop"],"uagb_featured_image_src":{"full":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40.jpg",3200,2368,false],"thumbnail":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40-150x150.jpg",150,150,true],"medium":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40-300x222.jpg",300,222,true],"medium_large":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40.jpg",3200,2368,false],"large":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40-1024x758.jpg",1024,758,true],"1536x1536":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40-1536x1137.jpg",1536,1137,true],"2048x2048":["https:\/\/www.mcfade.co.uk\/blog\/wp-content\/uploads\/2011\/03\/2015-05-29-20.08.40-2048x1516.jpg",2048,1516,true]},"uagb_author_info":{"display_name":"McFade","author_link":"https:\/\/www.mcfade.co.uk\/blog\/author\/admin"},"uagb_comment_info":2,"uagb_excerpt":"F stops, shutter speeds and ISO can be confusing. I like to think in terms of things I understand when trying to explain difficult concepts, and it happens that beer can be roughly equated to exposure&#8230; F-Stops So the F stop relates to how fast a beer flows from the pump:- Guinness takes ages, that&#8217;s&hellip;","_links":{"self":[{"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/posts\/261","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/comments?post=261"}],"version-history":[{"count":10,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/posts\/261\/revisions"}],"predecessor-version":[{"id":138146,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/posts\/261\/revisions\/138146"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/media\/5706"}],"wp:attachment":[{"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/media?parent=261"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/categories?post=261"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mcfade.co.uk\/blog\/wp-json\/wp\/v2\/tags?post=261"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}