Canon® EOS 5D Mark II Digital Field Guide

Glossary

ambient light

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

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 and f/5.6.

artifact

An unintentional or unwanted element in an image caused by an imaging device or appearing as a byproduct of software processing, such as compression, flaws from compression, color flecks, and digital noise.

artificial light

The light from an electric light or flash unit. The opposite of natural light.

Auto ISO

Considering the lighting, lens used, and exposure settings, the camera automatically selects an appropriate ISO for handheld shooting, from ISO 100-6400.

autofocus

The camera automatically focuses on a subject by using the selected autofocus point shown in the viewfinder or tracks a subject in motion and then creates a picture with the subject in sharp focus. Press the Shutter button halfway down to activate this.

automatic exposure

The camera meters the light in the scene and automatically sets the shutter speed (ISO) and aperture necessary to make a properly exposed picture.

automatic flash

When the camera determines that the existing light is too low to get either a good exposure or a sharp image, it automatically fires the built-in flash unit.

axial chromatic aberration

A lens phenomena that bends different color light rays at different angles, thereby focusing them on different planes. Axial chromatic aberration ...