my camera, the zone system, and twenty years

I’ve been taking pictures for a long time (far too long to have learned as little as I have!). When I was a teenager, I developed and printed black and white film, at the Salt Lake Art Center (now I can admit that I should have been paying for the darkroom time, but I simply walked in and used the equipment and chemicals, for months). In those days, they taught the Zone System. When I managed to get it right, it worked well, but it was tricky. Years later, I have a digital camera that produces decent exposure ranges straight out of the box, no thought by me required. Nonetheless, I thought I would look around for information on how to more directly control exposure.

The Zone System is (and here, people who know more will cringe) a way to plan how a picture’s lights and darks will be captured and printed. Spot meters that older cameras had (like my Minolta SRT-303) just measured the exposure off the part of the image in the middle of the frame, so if there was another part of the picture that was much darker or lighter, that part would be way too light or dark.

For example, if I took a picture of a person in a car in bright sunlight, the spot meter would tell me to expose for the sun reflected off the car, say 1/500 of a second at f/16 (with ISO 400 film). If I did that, everything but the hood of the car, including the person, would be completely black. Following the Zone System, I decide that the highlights on the car would be the brightest thing in the picture, and the person would be in the middle range. So, I increased the exposure 3 stops, to f/5.6, and the person’s face becomes visible (while the highlights on the car become pure white). It took a lot of practice to make these decisions, however.

Now, meters in cameras are using the entire image to decide the exposure, basically building in the Zone System into the camera’s exposure calculation (this is the “evaluative” mode my camera has). If you are interested in more direct exposure control, then, it seems that you are left with:

  • using the camera’s meter in spot mode, manual exposure, and using the traditional zone system
  • using the camera’s meter in evaluative mode, automatic exposure, and let the camera own the exposure

Neither one of these is particularly satisfying to me; the evaluative mode is better than I am at exposure calculation even if I set the exposure manually (since I still use the meter), and I really have no desire to go back to spot metering. I found a third option:

  • Underexpose everything, shoot in RAW mode, and adjust the values of the picture after it’s copied to the computer


This has produced the most satisfying results so far; without any special software or too much worry about exposure, I can still use my Zone System knowledge to peg parts of a picture to particular values of light and dark I choose.

  • I underexpose (I set the EV compensation to minus 2/3 stop) because digital cameras don’t capture as much information about the bright areas of the picture as film does, so I want to be sure I get whatever detail is in the highlights
  • I use RAW mode because it lets me change the exposure of the picture after it’s shot without losing any information
  • I adjust the exposure on the computer because I still want to decide what the most important part of the picture is (and what should get the ‘middle range’ in the photo). Almost all the time, this is as simple as adjusting is the white, grey, and black points (something every single program for handling digital photos can do; Picasa, iPhoto, etc.).

Sometimes I will set two or three other points to use a transfer curve in the RAW conversion, but not so much anymore. The photo above was taken in this way (I show it in black and white because I think it has a great middle dynamic range that illustrates the idea — the pretentiousness of black and white is just a bonus). Next, I am going to have to figure out how to get a handle on the weird white balance problems I have…

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