calculating film exposure
We now move on to another critical area of the Zone System - film exposure. Film exposure is primarily a function of shadow placement. So the questions for this level are a bit simpler in appearance that the questions for level 3.

All of the unnecessary information is removed to help you concentrate on the question at hand. The basic issue is, given the shadow meter reading and the shadow placement, for you to find the correct f-stop to set use during the exposure. In the field, only calculate your exposure after you have determined the correct luminance range, shadow placement and film development. The order that you make these calculations will play a role in the simplicity of thinking about each individual element of the mechanics of creating the image.

In the field, think in this order:

1. luminance range
2. shadow placement/highlight fall
3. film development
4. film exposure

The order above is mostly just a personal preference. The goal to think your way through the exposure and development calculations quickly and accurately. You or I can think accurately about things in another order, this one just seems to be the handiest. I also fit in other complicating factors, like film-speed shift do to film development, pre-exposure effects on the shadow placement, filter factors and more.

If you get into that thinking habit, you can then add additional bits of Zone System Power [TM] :-) as you acquire them. Let's say that you start using filters on your camera. The filter factors are easily applied last - that way, they have less complicating influence on the other elements you have to think about. You still have to consider the effect of using the filter on the placements of various areas of the subject along the grayscale, and the ramifications of those placemnets on your film development. However, you kept the numerical complications of the filter out of the exposure equation until the very end.

Or if you realize that you have to give semi-compensating film development you may need to adjust your filmspeed downward to allow extra support to the shadows. The list goes on, but the trick is to work in an orderly fashion within a framework that you are intimately familiar with

For level 4 questions, assume that the filmspeed and shutter speeds remain constant. You only have to determine the appropriate f-stop to use. Help for locating the appropriate f-stop can be found in Chapter 3.

For a bit of a jump start, here is part of the hint section for this set of questions: