September 7, 2006
Light meters measure the intensity of light. The light meter is used to determine the proper exposure. Most 35mm cameras have a built-in meter, called a through the lens meter. Light meters measure the amount of light and recommend an f-stop and shutter speed setting that produces middle gray. Middle gray is the average gray on a scale from white to black.
There are different types of light metering methods:
Reflective – measures the amount of light reflecting of a surface
Center-weighted or spot - focuses the metering on a very small portion of the scene (typically 1°~5° angle of view).
Matrix metering - divides the scene into 5 ~ 45 areas, meters each one independently, and using a computerized algorithm tries to determine the appropriate exposure value
My camera’s film speed can be set manually. However, my camera also has a built in DX code reader and can set the film speed automatically.