Shutter

DEFINITION:

A device which leads light into an optical system for a selected time and then shuts it out.

DESCRIPTION:

A shutter has two major functions. One is to control exposure so that the film is exposed to light for the correct length of time, and the other is to photograph moving objects without blurring (motion freezing ability). Generally, most of them are equipped with a synchronized flash system. Shutters are briefly classified into lens-shutter types and focal-plane shutter types.