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by Phil Ball

Q. My new camera gives me a choice between Spot, Evaluative and Center Weighted Average for metering. What’s the difference, and which should I use?

A. These are typical settings for many digital cameras, and it’s important to understand the difference between them.

Center Weighed Averaging, as its name implies, favors an area around the center of the frame. It’s assuming that your main subject is in the center (or near the center) of the picture you have composed. It meters the entire frame, but more heavily weights whatever is in the center of the frame when choosing the exposure it sets.

Evaluative metering does away with the center weighting, looks at the overall scene, and tries to come up with a reasonable exposure. Of course your eye sees a much wider range of lights and darks than the camera can see. Therefore you might have amazing results, or have areas of over or under exposure with evaluative metering. Because of this, some photographers seem to prefer center weighted metering, since it appears to give a more predictable result.

Spot Metering is the most precise metering technique. With spot metering you are only measuring the light reflected from a small area in the center of the frame, indicated by a set of brackets, or sometimes a small circle. This can be exactly what you need in some circumstances, if you need to be sure one specific face or object is metered properly.

Published: Courier 9/5/10 - Page 5C