From: carson@HQ.Ileaf.COM (Carson Graves)
Subject: re: the zone system for 35mm
Reply-To: carson@HQ.Ileaf.COM (Carson Graves)
Organization: Interleaf, Inc.
Date: Wed, 9 Sep 92 14:23:38 GMT

>From: usenet@adobe.com (USENET NEWS)
>Subject: Re: Zone system with 35mm?
>Message-ID: <1992Aug31.163835.28007@adobe.com>
>Organization: Adobe Systems Incorporated
>Date: Mon, 31 Aug 1992 16:38:35 GMT
>Lines: 24
>
>| ...fill your viewfinder with the palm of your hand and take 
>| a meter reading off of it... Open up your camera one-stop...
>| and take the picture.
>|
>| ...The bottom line is that the method I've outlined works 
>| perfectly and _does_ re-create the Zone System.
>
>                                  -Brian
>
>The method described is equivalent to placing skin tones (the palm 
>of the hand) on Zone VI. But where do the important shadow areas
>fall? Where do highlights fall? What is the contrast range? Metering
>your hand doesn't tell you any of these things, and only guarantees
>that midtones receive proper exposure. It's like describing how to
>drive a car by saying, "Open the car door, get in, close the door,
>put the key in the ignition and start the car." 
>
>What comes next?

>Metering your hand is a perfectly legitimate way to determine
>"normal" exposure for a normal subject. But to call it the Zone
>System is absurd!
>                   -Alan


I've been away on vacation the last 10 days, but I imagine I should
add my $0.02 worth here...

The above discussion leaves out some important points. First, 
Caucasian skin in the brightest ambient light is a Zone VI for the
purposes of making a literal interpretation of the tones in a scene. 
So, metering the palm of your hand while it is pointing in the direction 
of the light source is a good way to get a highlight reading for a scene 
that is in the same ambient light as your hand. So far, so good.

Second, (and part of what was apparently left out) is that Caucasian
skin tone in shadow is normally a previsualized Zone IV. This means
that if you take a reading of the palm of your hand while it is pointing
away from the direction of the light, you can get a reasonable
shadow reading. 

Assuming you are shooting negative film, you should base your exposure
on the shadow reading (close down one stop) and get a workable 
idea of the contrast by comparing the highlight and shadow readings.
(If you are shooting positive film - i.e. slides - then take the
highlight reading and open up one stop and don't worry about the
contrast as there isn't a lot outside your choice of film that will
affect it.)

This system is especially useful for (although not limited to) 35mm
photography, assuming you understand the nature of the materials
you are working with and limitations of the system. To mention
a few of the limitations:

- The hand in shadow, hand in light readings must be in the same
ambient light as the scene you are photographing. If you are standing
under a tree and the scene is a sunlit field, then this procedure
won't work.

- Using a Zone IV and Zone VI to determine exposure and contrast is
adequate for most purposes, but it is always more accurate to
use highlight and shadow zones that are farther apart (i.e. Zone III
and Zone VII, Zone II & Zone VIII, etc).

- As stated, Zone IV and Zone VI are the normal previsualized zones
for Caucasian skin in shadow & light. There are workarounds for people 
with darker skin tones that equally convenient. 

- The nature of roll film means that you can't develop each negative
individually for a specific contrast range. However, it is also the
nature of small roll film cameras that you usually shoot all or most
of a roll in the same general location and lighting. Some common
sense rules of thumb about how to develop your film would indicate that
you develop a roll for the contrast of the frames that are most
important to you or which predominate on that roll. If you choose 
to print any frames that are developed for the wrong contrast use paper
grades to compensate. There are also some simple rules you can apply 
when all frames on the roll are equally important and they are of a 
wide range of contrast. 

I think the above sums up the issues reasonably well, but if anyone
is interested in reading more, I can whole heartedly recommend
"The Zone System for 35mm Photographers," (Focal Press - ISBN
0-240-51773-3) written by someone whose name escapes me right 
now :-). A surprising number of libraries have it, but if not,
you can always order it from your local book store or from Light
Impressions.

Carson Graves
carson@Ileaf.HQ.com

At this point most people include a disclaimer disavowing any
financial interest, so I suppose I should add a "claimer" here. 
For every copy of the "ZS for 35mm Photographers" sold I get
roughly $2 (US) in royalties. Please, *everybody* buy a copy
so that I can quit my day job writing software documentation.
:-) :-) :-) :-) :-) :-) :-) :-)....
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