Autoexposure and Ansel Adams

June 2, 2010

Photo Tips

What if I told you autoexposure could bring you closer to the way that Ansel Adams shot? How could that be? I can tell you it works, so read on. And I challenge those manual exposure diehards to open their minds a little and see what is possible here.

First, some perspective. In brief, Ansel Adams’ Zone System is a way of exposing a scene so that bright areas are exposed properly as bright areas and dark areas are exposed properly as dark areas. Adams would create an exposure to place specific brightness values in a photograph based on both exposure and processing.

At one time, I was an absolute zealot about manual exposure. I used the Zone System, even modifying it a bit for color work. I used manual meters including spot meters to precisely meter a scene. Now I rarely use anything except autoexposure. So what happened

When I became editor at Outdoor Photographer magazine years ago, I got a lot of information from camera manufacturers on how great their metering systems were. In the 1990s, cameras began to have a huge amount of computing power built into them so that the camera metered multiple points in a scene then compared them to a database in order to create an optimum autoexposure. Today, this power is even more advanced, and includes information such as color and distance.

I figured I should understand this. I started shooting autoexposure and found that, indeed, it worked very well as long as you understood its weaknesses. Digital advanced exposure options with three things — the LCD which allowed highlight warnings (often called “blinkies”) and a histogram. Now I can shoot autoexposure and shoot using a variation on Ansel Adams Zone System.

In every scene, there are very bright areas. They need to be exposed so they record as the bright areas they are so that the rest of the scene gets the proper exposure. That is a critical part of digital photography exposure. If bright areas are too bright, they become washed out and lose color and tonality. If they are too dark, the dark parts of the scene become underexposed and you lose color and tonality there plus increase noise. While you can “recover” some color and detail in the computer if bright areas are recorded too bright or dark areas too dark, the image will never be as good as when they are exposed properly. The sensor simply does not do its best with color chroma (the color of color) and tonal range when exposure is outside of its optimum (central) range.

So here’s what I do. I use Aperture Priority autoexposure because it allows me to control f-stop for both depth of field and fast shutter speed. (The depth of field part is generally understood, however, if I choose a wide f-stop, I automatically get the fastest shutter speed possible for the light). As I look at the scene, I decide if it is average in tone, overall bright or overall dark. If the scene is average, I use the camera’s setting. If bright, I know the camera will tend to underexpose, so I use exposure compensation for more exposure. If dark, I know the camera will tend to overexpose, so I use exposure compensation for more exposure. That is the start of thinking like Ansel Adams. With a little experience and paying attention to what the camera is doing, anyone can make these judgements quickly.

Then I take a picture. I set up my LCD review so that it stays on for 8-10 seconds so I can quickly check the exposure. I want the brightest areas to either just start to blink with highlight warning or just quit blinking, depending on how important detail is in these areas. Now I hear some RAW purists who say that doesn’t work because this is based on a JPEG file. That’s true, but that is nitpicking based on technology theory rather than real photography because this system does work.

I quickly adjust exposure to get the right highlight warnings or I might look at the histogram to be sure there is no large gap on the right side (a big gap usually indicates underexposure and bright areas exposed too dark). I can do this whole thing very fast, much faster than doing a lot of manual readings and calculating exposure in my head. And I am using Ansel Adams system by exposing to place bright areas as bright areas in my exposure. This also keeps dark areas as bright as possible. And I get a quick look at the image with the highlight “zones” pointed out for me by the blinkies. Thank you Ansel and modern technology!

Check out my blog at http://www.photodigitary.com and follow me on Twitter at http://twitter.com/robsheppardfoto.


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This post was written by:

- who has written 27 posts on The Digital Photo Experience.

Rob Sheppard is the author/photographer of over 30 books, the editor-at-large for Outdoor Photographer magazine, and a nationally known presenter and workshop leader. His specialities are nature photography and helping photographers with digital technologies from getting the most from small sensors to Lightroom to Photoshop. Check out Rob’s websites at http://www.robsheppardphoto.com and http://www.natureandphotography.com


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One Response to “Autoexposure and Ansel Adams”

  1. Soren Hedberg Says:

    Great article, I went through the same cycle you described here (used to be full manual all the time, now use Av mode). People underestimate the metering that is in their cameras.

    Reply


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