A Quick Word About the Zone System

This is an afterthought to the last post on dynamic range, but let's take a quick look at the Zone System. This is something Ansel Adams and his buddy Fred Archer put together in the 1940's, originally designed for black and white film.

Basically they created their own 10-stop scale of tones from pure white to pure black (11 tones in all). This scale was supposed to represent the full range of black and white film and the paper it was ultimately printed on. Just to make things confusing, they labeled these zone "0" (zero) through "X" (roman numeral 10).

The idea was, the meter will always give you a reading for the middle gray tone "V" (5). Want to render whatever you just metered as zone "VII" (7, a light tone)? Overexpose by 2 stops. Want something to be zone "II" (2, a very dark tone), underexpose by 3 stops. Got it?

So why aren't we using the Zone System to talk about exposure? Well, first of all this scale represents the theoretical dynamic range of black and white sheet film, but all I care about the actual dynamic range of the digital camera I am using.

Second, I hate the numbering system. Roman numerals suck and are irritating to use. Also this doesn't match up to anything you see in modern cameras. Do I ever see a "VIII" or "IX" on my in-camera meter? No, I see "-2, -1, 0, +1, +2". Zero is metered value, not "V". Negative numbers are underexposure (darker), positive numbers are overexposure (brighter). That's pretty intuitive, right?

So that's why I more or less skipped the Zone System. This may make old school photography teachers want to cry, but I'm trying not to waste your life here. If you're shooting black and white sheet film and hand developing and printing it, learn the Zone System in depth, there are tons of books on it. If you're the other 99.99% of the population you can safely ignore it.