middle tone, which is why spot meters usually cannot be used without knowing the zone system. Sometimes green grass falls here.

+1 Stop (Zone VI): Medium light parts of an image. Skin and granite rocks go here. For most landscape photos you'll set your light rocks here, and the shadows at -2 stops. Bright yellow is set at +2/3 stops.

+2 Stops (Zone VII): White things like snow and sheets of white Fome-cor are set here.

+2.7 Stops (Zone VIII): This is where slide film goes clear.

This is how the zones of the classic zone system correspond to the analog bar graph on your exposure meter:

Zone II = -3 stops

Zone III = -2 stops

Zone IV = -1 stop

Zone V = +- 0 stops

Zone VI = +1 stop

Zone VII = +2 stops

Zone VIII = +3 stops

If you are lucky, all the elements in your image will fall within -2 to +2. Usually they won't. Sorry.

If your spot meter tells you that the shadows are darker than -2 stops that simply means they will be fairly black, and if the whites get too much hotter than +2 that they will be completely white or clear.

Slide film usually goes clear at +2.5 stops. It usually starts getting pretty murky at below -2 stops, although you can still see things down to -4 stops on Velvia.

You need to think as a painter does and ask yourself at what level of tone you want each part of your image to render. You need to be in control, and the Zone System lets you be in control. Otherwise you'll simply be gambling that your images will "turn out." With the Zone System you will know when you need to alter your lighting.

Problems

There will be plenty of occasions in nature where God is not putting the light range where you want it. The Zone System is useful here because it tells you before you waste a lot of film that you are probably going to get garbage and thus you can plan or change the light or filtration accordingly.

What do you do if the lightest and darkest parts of the scene are beyond the range of your film, typically +- 2 or 3 stops?

Simple: you have to change the lighting somehow. If you have a very high-contrast scene there is no correct exposure and you will never get what you want.

© 2007 KenRockwell.com

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converted by Sándor Nagy