Measuring Subject Contrast with InCamera Meters

The principles you have just learned apply as much to in-camera meters as any other type, but the above examples may have been confusing because in-camera meters don't use meter numbers like those used in my illustrations.

Instead of using EV numbers, an in-camera meter translates its readings of the Important Shadow and Highlight areas directly into recommended f/stop and shutter speed combinations. Let's briefly review how this works.

In-camera light meters have various ways of telling you that, "this is the correct exposure." When they are set to any of their automatic modes they simply read out a given combination of aperture and shutter speed. When they are in a manual mode you have to change your aperture or shutter speed until your electronic display is centered. As we learned in the previous chapter, in either of these cases, the exposure that results will cause what the meter is seeing to print as Zone V.

The important thing to remember is that when the meter is seeing something that you want to print as Zone III, the meter's recommended exposure will be two full stops too light!

Conversely, if the meter is pointing to something you want to be Zone VII, its recommended exposure will be two stops too dark.

This translates into a reliable way to use in-camera meters to measure the contrast of any subject.

To make the steps in this process more clear it's useful, when you are beginning to learn this system, to use a Zone Metering Form as illustrated in Figure 38 to organize your readings.

See Appendix Q for a blank version of this form that you can copy for this purpose.

As I mentioned above, in order to measure the contrast of any scene you have to make at least two meter readings; one of the Important Shadow and another of the Important Highlight.

To simplify the process of comparing these two readings, think of either your shutter speed or your aperture as the Reference Reading that will remain the same from one reading to the other. I normally use the shutter speed as my fixed Reference Reading and apertures as Measurement Readings that change, as you will see in the following example.

Looking again at the portrait in Figure 32, here is how you would use the Zone System to measure the contrast and determine the proper exposure using an in-camera meter.

Note: Either Manual or Automatic modes can be used for this process.

1. Get close enough to fill the frame of your camera with the Important Shadow Area (previsualized in this case as Zone III).

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