Small-Format Cameras, Continued
Film release
The film-release button, located on the bottom of camera bodies, releases the
tension on the film roll winding inside the camera body. Make sure you
depress the film release before attempting to rewind film into the canister or
preparing a double exposure. Not releasing tension on the film will tear film
and sprocket holes. The film release does not open the film back or expose
film.
Light meters
A light meter inside the camera body reads the amount of light entering the
lens and recommends an overall ideal aperture setting. Most 35mm SLRs
have built-in light meters that read through the lens (TTL). Light meters
may read light falling on the mirror, the shutter curtain, the focusing screen,
or the film surface and produce a display in the viewfinder indicating the
correct exposure setting. In the manual mode, set the lens aperture to
correspond with the meter reading. In the automatic mode, the camera sets
the exposure and informs you of the setting. To compensate for unusual
lighting conditions or for creative effect, override the automatic selection and
manually set the aperture. Light meters in 35mm cameras are ordinarily
powered by batteries.
Figure 7-13 shows a light meter reading from the eyepiece of a camera.
Figure 7-13.—A TTL light meter reading of f/8 from
the eyepiece of a camera.
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