METERING

All camera meters assume that an average of all the tones in a scene equates to
18 percent gray.  At one time a gray card was part of photographer's camera bag.

The term "metering pattern" refers to how a camera's exposure system measures
not only the amount of light in the scene, but also how the light varies within the
scene.  Most cameras offer a choice of metering patterns, each of which measures
in different ways. Type metering systems are listed below:

Centre-Weighted average metering - The oldest of all the metering patterns, it
takes an average reading of the scene, with emphasis given to the 70 percent of
the frame. Some believe this mode is best when shooting portraits where the
subject is the middle of the composition and the background is darker or lighter
than the subject.

Spot metering - meters just a small portion of the frame and ignoring the rest
of the scene.

Multizone Metering - meters divides the scene into a number of zones with
a reading taken from each.  Some zones are given a higher priority than others
and makes a decision on the final exposure.  This is the most common type of
metering pattern and provides the highest ratio of success as it works in most
situations. In my Nikon camera, this pattern is called " Matrix".