The Zone System

In 1939-40 the pioneering photographers Ansel Adams and Fred Archer developed (no pun intended) an exposure system based on this fact, a system that is still used today. It is called the Zone system, and is quite possibly the most useful piece of photographic knowledge you’ll ever learn. There are several variations on the original system, but I’ll go with the one that is easiest to understand.

Starting with 18 per cent grey as the mid-point, the system divides all the tones between black and white into 11 zones, numbered 0-10. Zone 0 is featureless black with no details visible, which in your image editor would have an RGB value of 0,0,0. Zone 10 is pure white with no details visible, and an RBG value of 255,255,255. The mid-tone 18 per cent grey is zone 5, and should have an RGB value of about 127,127,127.

Theses zones represent exposure values, or EV. The difference between one zone and the next is equivalent to the difference between one exposure setting and another one exactly one stop higher or lower.

This is probably a good time to take a slight detour and explain how exposure is controlled.


May 13, 2015, 5:40 pm

I've just moved from a now fairly old Nikon DSLR to a more compact Compact System Camera and was disappointed to see this happening. Yes in the old days I used to dial in compensation, but Nikon have a "Scene recognition system" that seems to reliably detect these scenarios and correct. I'm now having to go around even fairly mundane shots and dial in exposure compensation. I'd have expected a modern (2013 in this case) compact system camera, with its view of the _whole_ picture not a "1024 point metering matrix" would do better than a 2008 SLR.

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