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The Simplified Zone System

© Wendy Folse

When Ansel Adams perfected his Zone system, he took into account every part of his photographic system and then measured and quantitified each process. This allowed him to be able to precisely predict how each scene could be reproduced within his system. The major point of focus that must be remembered is that Ansel Adams was using sheet film, not 35mm film. His system worked because he could shoot and develop each negative using his precise calculations.

This does not work well for 35mm film because in order to control the precise development of each frame, they would all have to be shot with the exact same exposure values.

Today the Zone system is still much talked about and in some forms it is still used as Ansel Adams intended it to be used. However, it is most often used as a method for determining exposure values based on tonal ranges of a scene.

It is difficult to condense the entire Zone system into a few words and display it here but I will try to give you an easy "take what you will" example.

The Zone system breaks the range of light values into 10 zones from key black to paper white. Each zone represents one fstop.

• Zone 9 pure white +4
• Zone 8 white with little detail +3
• Zone 7 greyish-white highlights +2
• Zone 6 light grey +1
• Zone 5 18% grey 0
• Zone 4 darkish grey -1
• Zone 3 blackish grey -2
• Zone 2 greyish black some texture -3
• Zone 1 Black with little detail -4
• Zone 0 key black no detail -5

That amounts to a range of 9 stops. Not all films, especially 35mm, can handle nine stops nor can the paper. So the whole idea is to use the scale to move the desired tonal range within an acceptable range.

We know that all meters give exposure values based at 18% grey (Zone 5). If you metered on black skin, the meter would give you a reading in order to render the skin color 18% grey. That will not make the client very happy. So where do you put the skin tone to be most accurate? At about Zone 4. That means that you would take the exposure reading from the meter and then set the ev for -1.

For Caucasian skin it should fall at about Zone 6. (+1) For Pale Northern European Skin types it would be Zone 7 (+2)

The purpose for spot reading the shadows and the highlights is to understand the total range of the scene and then decide which points are important and which ones are less important. Obviously a person's face is more important so you would set the exposure for that feature. Then you figure out what details you will loose in the process. You may add light to the scene to increase the zone of a shadow detail in order to move it into an appropriate zone.