Canon® EOS Rebel XSi/450D Digital Field Guide

Glossary

A-DEP

(Automatic depth of field) The camera mode that automatically calculates sufficient depth of field for near and far subjects within the coverage of the seven AF focusing points, such as when several people are sitting at various distances from the camera.

AE

Automatic exposure

AE lock

(Automatic Exposure Lock) A camera control that lets the photographer lock the exposure from a meter reading. After the exposure is locked, the photographer can then recompose the image.

ambient light

The natural or artificial light within a scene. Also called available light.

angle of view

The amount or area seen by a lens or viewfinder, measured in degrees. Shorter or wide-angle lenses and zoom settings have a greater angle of view. Longer or telephoto lenses and zoom settings have a narrower angle of view.

aperture

The lens opening through which light passes. Aperture size is adjusted by opening or closing the diaphragm. Aperture is expressed in f-numbers such as f/8, f/5.6, and so on. See also f-number.

aperture priority

(Av Aperture-priority AE) A semiautomatic camera mode in which the photographer sets the aperture (f-stop), and the camera automatically sets the shutter speed for correct exposure.

autofocus

A function where the camera focuses on the subject when you press the Shutter button. In Basic Zone modes the camera automatically focuses on the subject using the autofocus point or points shown in the viewfinder, or tracks a subject in motion and creates a picture with the subject in sharp ...