With the advent of digital cameras people don\u2019t understand exposure so well any more.\u00a0 It\u2019s not like in the early SLR days where the cameras didn\u2019t have built in light meters.\u00a0 You had to use a hand held light meter or, lacking that, just guess.\u00a0 There was no way you could get along without knowing ISO (ASA at the time), shutter speeds and f\/stops.\u00a0 But that\u2019s all changed now and probably not for the better, at least if you want to take photographs that make an impact.<\/p>\n
<\/p>\n
Exposure is one of the fundamentals that you have to get right or, no matter how well you\u2019ve done everything else, you won\u2019t have an image.\u00a0 Yes, with RAW files we have some leeway and our sensors have increasingly impressive dynamic ranges.\u00a0 But a bad exposure will ruin an otherwise great photograph.<\/p>\n
So where to start in mastering exposure?\u00a0 Well, let\u2019s start in Norway and Italy.\u00a0 What?\u00a0 Yes, Norway and Italy.\u00a0 Put a Norwegian and an Italian on the beach right next to each other and see which one gets sunburned first.\u00a0 The Norwegian may start to burn in just an hour because of his fair skin while the Italian may take four hours to get the same level of sunburn because of the Italian\u2019s olive complexion.\u00a0 Our Italian friend requires four times as much sunlight as our Norwegian friend to get the same amount of sunburn. To look at this the other way, fair skinned Norwegians are four times more sensitive to sunlight than Italians with their olive skin.\u00a0 (Please don\u2019t take these numbers as medical fact because they\u2019re not.\u00a0 I\u2019m pulling them out of the air to illustrate a point.)<\/p>\n
We\u2019re going to see very soon that mastering exposure come down to a very simple concept \u2013 we use multiple of two (2) when determining the amount of light needed to make a correct exposure.\u00a0 Everything that we\u2019ll be talking about comes down to doubling or halving light.<\/p>\n
That said, we can control the sensitivity of the sensors in our digital cameras.\u00a0 We can make them very sensitive to light like the Norwegian or much less sensitive to light like the Italian.\u00a0 The level of sensitivity is set by the ISO control.\u00a0 Low numbers mean low sensitivity and high numbers mean high sensitivity.\u00a0 For many cameras the lowest ISO number is 100 or 200.\u00a0 Let\u2019s use 100 as our lowest ISO setting.\u00a0 So if we change the ISO from 100 to 200 we doubled the ISO number and therefore doubled the sensitivity.\u00a0 And by double the sensitivity, we need half the amount of light to get the same exposure.<\/p>\n
So to relate this idea to our Norwegian and Italian friends, the Italian could be said to have a skin ISO of 100 and the Norwegian, 400.\u00a0 This is because it took the Italian 4 times as long (4 times as much light) as the Norwegian to start to burn.\u00a0 Or, the Norwegian was four times more sensitive to light as the Italian \u2013 hence ISO 100 for the Italian and 400 for the Norwegian.<\/p>\n
But there\u2019s another aspect to exposure that we need to introduce at this point.\u00a0 Let\u2019s move our Norwegian and Italian friends from the beach at sea level and put them on the shore of a lake in Switzerland at an elevation of 10,000 feet.\u00a0 Now, at 10,000 feet half the oxygen in the atmosphere is below you and the same goes for the sunlight blocking effect.\u00a0 In other words, sunlight is two times as bright at 10,000 feet as it is a sea level.<\/p>\n
So our Norwegian will now get a sunburn in half an hour instead of one and our Italian will get the same amount of sunburn in two hours instead of four.\u00a0 The important thing to note here is when the intensity of the light doubles the length of time to get burned is halved \u2013 again, factors of two.\u00a0 And the take away for photography is, given the same ISO, we need to adjust the amount of light falling on the sensor to balance the intensity of the light in our scene,\u00a0 Basically, the sensor has an optimum amount of light necessary to give a correct exposure and that optimum amount of light is determined by the ISO.<\/p>\n
By the way, this doubling or halving of the amount of light is called a \u201cstop.\u2019\u00a0 In other words, if we double the amount of light we increase it by 1 stop.\u00a0 If we halve the amount of light we decrease it by 1 stop.\u00a0 The same goes with sensitivity or ISO.\u00a0 Doubling the ISO from 100 to 200 increases the sensitivity\u00a0 by 1 stop which then decreases the amount of light needed for a correct exposure by 1 spot.\u00a0 Double the ISO again (now 400) and we\u2019ve increased the sensitivity by another stop for a total of two stops (two doublings).\u00a0 In fact, our Norwegian is 2 stops (4 times) more\u00a0 sensitive to light than our Italian. And at 10,000 feet the light is 1 stop more intense than at sea level.<\/p>\n
So where are we?\u00a0 We can control the sensitivity of our camera\u2019s sensor with the ISO setting.\u00a0 And we need to be aware of the amount of light in the scene so that we can provide the sensor with just the right amount to make a proper exposure.\u00a0 That\u2019s what the camera\u2019s light meter attempts to do \u2013 measure the amount of light in the scene, take into account the ISO setting of the sensor and set the shutter speed and f\/stop to deliver the correct amount of light.<\/p>\n
So that brings us to two more variables we can control \u2013 shutter speed (the duration of the light passing through the lens) and f\/stop (the intensity of the light).\u00a0 Let\u2019s look at shutter speed first, keeping in mind that we are still dealing with factors of 2.\u00a0 Shutter speeds are measured in seconds or fractions thereof with the longest being 30 sec. and the shortest as short as 1\/4000 sec.\u00a0 Now, you probably think that it\u2019s pretty obvious that if I change the shutter speed from a half a second to a full second I just doubled the amount of light passing through the lens.\u00a0 And that\u2019s what we do with shutter speed \u2013 increase or decrease the amount of light by increasing or decreasing the length of time the shutter is open.\u00a0 Now here are the landmark shutter speeds that we need to keep in mind, realizing that each varies by 1 stop.\u00a0 Beginning at 1\/1000 and working down, the shutter speeds are<\/p>\n
1\/1000, 1\/500, 1\/250, 1\/125, 1\/60, 1\/30, 1\/15, 1\/8, 1\/4, 1\/2 and 1.<\/p>\n
By the way, the corresponding numbers you\u2019ll see on your camera are<\/p>\n
1000, 500, 250, 125, 60, 30, 15, 8, 4, 0\u201d5, 1\u201d<\/p>\n
We should note here that most digital cameras allow you to adjust ISO, shutter speeds and f\/stops by fractions of a stop \u2013 usually 1\/3rd stop but sometimes 1\/2 stop.\u00a0 So between each ISO number, shutter speed or f\/stop mentioned here there are two additional settings.\u00a0 But the ones we\u2019re talking about here are all one-stop differences and that\u2019s the important thing to understand.<\/p>\n
So that leaves f\/stop.\u00a0 Changing the f\/stop is like changing the intensity of the light passing through the lens.\u00a0 Shutter speed changes the duration and f\/stop changes the intensity.\u00a0 In our example, changing the f\/stop is like our friends putting on sun screen.\u00a0 If a coating of sunscreen doubles the length of time it takes to get a sunburn, then in photographic terms that\u2019s like decreasing the intensity of the light by 1 stop.\u00a0 If we use a stronger sun screen and it quadruples the length of time it takes to get a burn the intensity of the light was decreased by 2 stops.\u00a0 And now, back to f\/stop.<\/p>\n
So far ISO and shutter speed make sense; they\u2019re logical.\u00a0 Double the ISO and you double the sensitivity.\u00a0 Double the shutter speed (the length of time the shutter is open) and you double the mount of light.\u00a0 But f\/stop appears at first to be totally illogical.\u00a0 Well, it\u2019s only logical if you have a flair for mathematics.\u00a0 It turns out f\/stop is defined as the focal length of the lens divided by the diameter of the opening of the aperture\u00a0 And the aperture is that adjustable \u2018pupil\u2019 in the leans that can be opened and closed, just like the pupil of your eyes, to increase or decrease the intensity of the light.\u00a0 The result of this definition is that it makes f\/stops appear to work backwards.\u00a0 In other words, an f\/1.4 admits more light through the lens (has a wider opening) than f\/16 \u2013 yea, backwards.\u00a0 The other thing that makes f\/stops difficult to master is the fact that, even though we\u2019re still changing the amount of light by a factors of 2, the numbers don\u2019t reflect that.\u00a0 For example, when shooting at f\/1.4, to cut the amount of light in half means you would select an aperture of f\/2, not f\/2.8.\u00a0 So the sequence of f\/stops from the smallest aperture to the largest at 1 stop intervals looks something like this\u2026<\/p>\n
f\/22, f\/16, f\/11, f\/8, f\/5.6, f\/4.0, f\/2.8, f\/2.0, f\/1.4 and f\/1.0<\/p>\n
Is it important to know these numbers?\u00a0 Yes, I think so.\u00a0 But they\u2019re not as hard to learn as you might expect.\u00a0 If you look at the numbers you\u2019ll see a pattern.\u00a0 So, just remember two adjacent numbers like 1.0 and 1.4 and you can go from there.\u00a0 Do you see the pattern?<\/p>\n
One more thing to note about f\/stops is that your lenses all have a maximum aperture.\u00a0 Many lenses have a maximum aperture of around f\/4.0 or f\/5.6.\u00a0 But some more expensive lenses have a maximum apertures of f\/2.8 or even f\/2.0, f\/1.4 or in a few cases f\/1.0.\u00a0 Lenses with larger maximum apertures are referred to as \u2018fast\u2019 lenses because they work better in low light situation.\u00a0 But fast lenses are more expensive and a lot heaver because they require a lot more glass.<\/p>\n
Putting it all together we start with the brightness of the scene we\u2019re photographing.\u00a0 Next we set the ISO to select the sensitivity of our camera\u2019s sensor.\u00a0 At that point the camera\u2019s light meter tries to determine the correct shutter speed and f\/stop.\u00a0 If you have your camera\u2019s mode set to aperture priority (Av) then you specify the f\/stop and the camera selects the shutter speed.\u00a0 If the camera\u2019s mode is shutter priority (Tv) then you specify the shutter speed and the camera selects the f\/stop.<\/p>\n
Most landscape photographers shoot aperture priority (Av) at the lowest possible ISO.\u00a0 Why?\u00a0 Because the low ISO gives the highest quality image and the f\/stop controls depth of field.\u00a0 But there are times when shooting in shutter priority or even manual makes mode makes the most sense so you need to be familiar with all the modes and know when and how to use them.<\/p>\n
I hope this \u2018sunburn\u2019\u00a0 analogy helps explain the concepts of exposure in terms that we\u2019ve all been painfully familiar with at one time or another.<\/p>\n
I hope you\u2019re finding good light.<\/p>\n
Join me on an upcoming workshop.\u00a0 Click here for more details.<\/a><\/p>\n http:\/\/ralphnordstromphotography.com\/workshops\/To see more of my photographs click here.<\/a><\/p>\n (956)<\/p>\n","protected":false},"excerpt":{"rendered":" With the advent of digital cameras people don\u2019t understand exposure so well any more.\u00a0 It\u2019s not like in the early SLR days where the cameras didn\u2019t have built in light meters.\u00a0 You had to use a hand held light meter or, lacking that, just guess.\u00a0 There was no way you could get along without knowing … Continue reading “Mastering Exposure”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[281,4],"tags":[266,265,1358],"class_list":["post-1409","post","type-post","status-publish","format-standard","hentry","category-expoure","category-how-to-articles","tag-exposure","tag-photographic-workshop","tag-workshops"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p9Nl7-mJ","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1409","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/comments?post=1409"}],"version-history":[{"count":4,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1409\/revisions"}],"predecessor-version":[{"id":4605,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1409\/revisions\/4605"}],"wp:attachment":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/media?parent=1409"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/categories?post=1409"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/tags?post=1409"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}