Automatic Exposure; Three kinds are available: programmed auto exposure, aperture-priority auto exposure and shutter-priority auto exposure.

Lens with built-in autofocus drive motor. CPU is also built in. AF-I Nikkor lenses send information on distance to the camera body and are classified as D-type AF Nikkor lenses.

Automatic index; Nikon’s system for telling the camera’s exposure meter what the lens’ maximum aperture is.

Automatic index/Shutter; Nikon’s lens mount permitting automatic operation in shutter-priority and program auto-exposure systems.

The variable opening produced by the iris-diaphragm through which light passes to the film plane. Measured in f/stops.

Autoexposure systems wherein the photographer selects the aperture and the camera selects the appropriate shutter speed.

Apochromatic; a type of lens which focuses different wavelengths of light on the filmplane for improved image sharpness. Especially useful in telephoto lenses. (Chromatic aberration is corrected).

American Standards Association; (see ISO).

At the B setting, the shutter remains open as long as the shutter release button remains fully depressed.

Take a series of pictures at different exposures.