{"id":1757,"date":"2011-03-21T16:27:43","date_gmt":"2011-03-22T00:27:43","guid":{"rendered":"http:\/\/ralphnordstromphotography.com\/wordpress\/articles\/how-to-articles\/mastering-exposurehistograms-part-3\/"},"modified":"2018-09-09T20:17:19","modified_gmt":"2018-09-10T04:17:19","slug":"mastering-exposurehistograms-part-3","status":"publish","type":"post","link":"https:\/\/ralphnordstromphotography.com\/wordpress\/2011\/03\/21\/mastering-exposurehistograms-part-3\/","title":{"rendered":"Mastering Exposure–Histograms Part 3"},"content":{"rendered":"

This is the third post in a continuing series on the oft misunderstood but oh so important histogram.\u00a0 In the first two posts we discussed the histogram in general.\u00a0 If you missed them, click on these links.<\/p>\n

Mastering Exposure \u2013 Histograms Part 1<\/a><\/p>\n

Mastering Exposure \u2013 Histograms Part 2<\/a><\/p>\n

Recap<\/h3>\n

To recap, the histogram displays a graph of the tonal values in the scene you are about to photograph.\u00a0 It shows how the dynamic range of the scene matches and fits into the dynamic range of your camera\u2019s sensor.\u00a0 There are two critical pieces of information a histogram tells you:<\/p>\n

    \n
  1. If your exposure is correct<\/li>\n
  2. If you have problems capturing the dynamic range of the scene<\/li>\n<\/ol>\n

    To recap, the exposure is displayed by the position <\/strong>of the histogram curve within the boundaries of the graph area.\u00a0 As you increase the exposure the histogram moves to the right.\u00a0 As you decrease the exposure it moves to the left.\u00a0 If the exposure is increased so that the histogram moves all the way up against the right side of the graph area you will have highlight clipping. Likewise, if it moves all the way to the left side you will have shadow clipping.<\/span><\/p>\n

    The dynamic range of the scene is displayed as the breadth <\/strong>of the histogram,\u00a0 The wider the histogram the greater the dynamic range of the scene.\u00a0 The narrower the histogram the lower the dynamic range.\u00a0 When the histogram is so wide that it extends from one end of the graph area to the other you are facing a situation where your camera\u2019s sensor will have a difficult time capturing the full dynamic range of the scene.\u00a0 The worst case is you will have both highlight and shadow clipping.<\/span><\/p>\n

    <\/h3>\n

    <\/p>\n

    Shape<\/span><\/h3>\n

    Sometimes I hear people expressing concern about the shape of the histogram.\u00a0 They\u2019ll ask me, ‘\u201dIs this a good shape?\u201d or \u201cI don\u2019t like the shape.\u00a0 What can I do to fix the shape?\u201d\u00a0 Basically there\u2019s nothing you can do about the shape because it is determined by the scene, the amount of light and dark areas.<\/p>\n

    But being aware of the shape can help prepare you for challenges you may encounter as you capture the image and later on in the post processing.<\/p>\n

    I find it useful to categorize the histogram shapes into four general types \u2013 Rocky Mountain, mole hill, Grand Canyon and HDR.\u00a0 The Rocky Mountain histogram is broad and may have many peaks.\u00a0 It can fill a large portion of the graph area.\u00a0 The mole\u00a0 hill histogram is narrow, often with a single peak but it may have a few.\u00a0 It has lots of room on either side and doesn\u2019t even come close to filling the graph area.\u00a0 The Grand Canyon histogram has two major peaks, one in the shadow area and the other in the highlight and is separated by a huge canyon.\u00a0\u00a0\u00a0 The HDR histogram extends from one edge of the graph area to the other and very likely has highlight clipping, shadow clipping or both.<\/p>\n

    In this and the following posts I\u2019ll discuss each of these shapes in detail and offer suggestions of how to expose for them and how to treat them in post processing.<\/p>\n

    Rocky Mountain Histogram<\/h3>\n

    Let\u2019s begin with the Rocky Mountain histogram.\u00a0 It\u00a0 basically fills most of the graph area.\u00a0 It may have many peaks.<\/p>\n

    You typically encounter the Rocky Mountain histogram in the middle of sun filled days.\u00a0 You have bright, sunny areas, deep shadows and a continuous range of tonalities in between.<\/p>\n

    Here\u2019s an example of a Rocky Mountain histogram.<\/p>\n

    \"rocky_mountain_1\"<\/a><\/p>\n

    It is the histogram of this photograph taken at Devil\u2019s Golf Course in Death Valley.<\/p>\n

    \"Death_Valley_WS_110214__A1P0133\"<\/a><\/p>\n

    Devil\u2019s Golf Course is an amazing area filled with jagged slabs of salt.\u00a0 Salt saturated ground water seeps up and evaporates, leaving behind salt crystals that accumulate into these fantastic shapes.<\/p>\n

    Understanding the Histogram<\/h3>\n

    This image has bright areas, particularly the sky and the parts of the salt slabs that are in direct sunlight.\u00a0 These bright areas contribute to the right side of the histogram.\u00a0 The area also has a lot of shadow areas, especially in the bottom half of the image.\u00a0 The amount of shadow area is greater than the amount of bright area, contributing to the large peak on the left end of the histogram.\u00a0 There is also a continuous range of tonalities from the darkest area (far left side of the histogram) to the brightest (far right side) so there are no significant gaps or valleys.<\/p>\n

    The histogram fills nearly all of the graph area indicating that the dynamic range of the scene pretty closely matches that of the camera\u2019s sensor.\u00a0 More importantly, the dynamic range of the scene does not exceed the camera sensor\u2019s dynamic range.\u00a0 This we know because the histogram does not touch both sides of the graph area but ends just a little short.\u00a0 This is a good thing because we won\u2019t have clipping problems with this image.<\/p>\n

    In the Field<\/h3>\n

    The thing you want to think about in the field is to make sure this image is not over or under exposed.\u00a0 Over exposing will introduce highlight clipping and underexposing will give you shadow clipping.\u00a0 We can tell the image in the example is properly exposed because, as mentioned above, the histogram does not touch either end of the graph area.<\/p>\n

    Over exposure results in the entire histogram shifting to the right.\u00a0 Let\u2019s take a look.<\/p>\n\n\n\n
    \n

    \"Death_Valley_WS_110214__A1P0135\"<\/a><\/p>\n<\/td>\n

    		\n

    \"rocky_mountain_over\"<\/a><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    The image was over exposed by 1 1\/3 stops and is washed out as we would expect.\u00a0 And the histogram now has shifted well to the right with a large spike climbing the right wall.\u00a0 This is where the clipping occurs which is largely in the sky but also in some hot spots on the salt.\u00a0 There\u2019s a very real possibility that this clipping cannot be recovered in post processing, even with a RAW image.\u00a0 When over exposed like this there\u2019s a high chance the image cannot be recovered.<\/p>\n

    Under exposure results in just the opposite.\u00a0 The histogram will move to the left.\u00a0 Here\u2019s what that looks like.<\/p>\n\n\n\n
    \n

    \"Death_Valley_WS_110214__A1P0134\"<\/a><\/p>\n<\/td>\n

    		\n

    \"rocky_mountain_under\"<\/a><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    This image was under exposed by 1 1\/3 stops.\u00a0 In this case we didn\u2019t get any shadow clipping.\u00a0 The histogram moved to the left but did not move all the way to the left side of the graph area.\u00a0 This image is still very workable.\u00a0 This is actually closer to what we would like the final photograph to look like.<\/p>\n

    For comparison purposes here are the three exposures and their histograms.<\/p>\n\n\n\n\n\n
    \n

    \"Death_Valley_WS_110214__A1P0133\"<\/a><\/p>\n<\/td>\n

    		\n

    \"rocky_mountain_1\"<\/a><\/p>\n<\/td>\n<\/tr>\n

    \n

    \"Death_Valley_WS_110214__A1P0135\"<\/a><\/p>\n<\/td>\n

    		\n

    \"rocky_mountain_over\"<\/a><\/p>\n<\/td>\n<\/tr>\n

    \n

    \"Death_Valley_WS_110214__A1P0134\"<\/a><\/p>\n<\/td>\n

    		\n

    \"rocky_mountain_under\"<\/a><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    Notice that while the histogram\u2019s shape changed a bit as the exposure was varied it kept its basic shape of a large peak in the shadow area turning into smaller peaks as we move towards the highlights.<\/p>\n

    In the field I almost always shoot aperture priority, especially in situations like this.\u00a0 The reason is to control depth of field which is critical for this photograph.\u00a0 If the depth of field requirements are extreme I may need to shoot at f\/16 or even f\/22.\u00a0 Since the camera is on a tripod, the shutter speed is not important.<\/p>\n

    So it is important to check the histogram after the initial shot to make sure the image isn\u2019t severely over or under exposed.\u00a0 If so, exposure compensation must be applied to correct the exposure.\u00a0 The basis for making this decision is the position of the histogram relative to each end of the graph area.\u00a0 In this case if the over exposed image had been our initial shot we would have applied a correction of \u20131 1\/3 exposure compensation.<\/p>\n

    HDR<\/h3>\n

    It\u2019s worth mentioning at this point that the three images are what you would get if you were shooting HDR.\u00a0 Without going into all the detail just now, the first image is the middle exposure and captures the mid-tones.\u00a0 The second image is the over exposure that captures the shadows and the third image is the underexposure that captures the highlights.<\/p>\n

    Post Processing<\/h3>\n

    The Rocky Mountain histogram poses no particular challenges when it comes to post processing.\u00a0 No special techniques are required.<\/p>\n

    We could work with either the middle exposure or under exposed image as neither of them have any clipping.\u00a0 I\u2019ll choose to work with the first image, the middle exposure.\u00a0 I won\u2019t go into the specific adjustments here but just outline the decisions I make.<\/p>\n

    We’ll want to darken the image to make make it richer.\u00a0 Darkening it will bring out more of the blue in the sky, add contrast and increase the color saturation.\u00a0 I like to take a somewhat systematic approach to post processing, adjusting the tonality or luminance first, then the hue or color and finally the saturation.<\/p>\n

    Proceeding with the tonality, I\u2019ll first adjust the overall brightness and contrast.\u00a0 And the very first tonality adjustment is to set a black point; \u2013 some small area of the image that will be pure black.\u00a0 This establishes a tonal foundation for the entire image.\u00a0 The next thing I did was to darken the sky.\u00a0 And finally I adjusted the mid tones to product a pleasing amount of contrast.\u00a0 Here are the results.<\/p>\n

    \"Death_Valley_WS_110214__A1P0133_tonality\"<\/a><\/p>\n

    The second thing I do is adjust hue or color.\u00a0 This image doesn\u2019t need a lot in the way of hue adjustment.\u00a0 The change is very subtle.\u00a0 It\u2019s a little cooler to help bring out the cyan in the sky and shadows.<\/p>\n

    \"Death_Valley_WS_110214__A1P0133_hue\"<\/a><\/p>\n

    The final adjustment is saturation.\u00a0 I focused on the red and yellow found on the salt (caused by the low angle sun) and the cyan in the sky and shadows.<\/p>\n

    \"Death_Valley_WS_110214__A1P0133_saturation\"<\/a><\/p>\n

    Here\u2019s a before and after comparison.<\/p>\n\n\n\n
    \n

    \"Death_Valley_WS_110214__A1P0133\"<\/a><\/p>\n<\/td>\n

    		\n

    \"Death_Valley_WS_110214__A1P0133_saturation\"<\/a><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    As you can see, the post processing is where the magic happens.\u00a0 But you must start with a good capture.<\/p>\n

    In subsequent posts I\u2019ll discuss the mole hill, Grand Canyon and HDR histograms.\u00a0 These are a bit more challenging and require some special techniques.\u00a0 Stay\u00a0 tuned\u2026.<\/p>\n

    Join me on an upcoming workshop.\u00a0 Click here for more details.<\/a><\/p>\n

    To see more of my photographs click here.<\/a><\/p>\n

    (2337)<\/p>\n","protected":false},"excerpt":{"rendered":"

    This is the third post in a series on the histogram. This post discusses the Rocky Mountain histogram, what it is, when you can get it, how to photograph and how to do the post processing.<\/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":[281,296,4],"tags":[32,87,279,267,15,226,93],"class_list":["post-1757","post","type-post","status-publish","format-standard","hentry","category-expoure","category-histogram-how-to-articles","category-how-to-articles","tag-california","tag-death-valley","tag-histogram","tag-mastering-exposure","tag-national-park","tag-phorography","tag-workshop"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p9Nl7-sl","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1757","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=1757"}],"version-history":[{"count":1,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1757\/revisions"}],"predecessor-version":[{"id":4035,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/posts\/1757\/revisions\/4035"}],"wp:attachment":[{"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/media?parent=1757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/categories?post=1757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ralphnordstromphotography.com\/wordpress\/wp-json\/wp\/v2\/tags?post=1757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}