Canon® EOS Rebel T2i/550D Digital Field Guide

Glossary

720p/1080i/1080p

High-definition video recording standards that refer to the vertical resolution (the number of horizontal lines on the screen) — either 720 or 1080 lines. Seven hundred twenty horizontal lines translate to a width of 1280 pixels, and 1080 lines translate to 1920 pixels of horizontal resolution. The p stands for progressive scan, which displays the video frame all at once. The i stands for interlaced, an analog compression scheme that allows 60 frames per second (fps) to be transmitted in the same bandwidth as 30 fps by displaying 50 percent of the video frame at a time.

AE

Automatic exposure.

AE Lock (Automatic Exposure Lock)

A camera control that enables the photographer to decouple exposure from autofocusing by locking the exposure at a point in the scene other than where the focus is set. AE Lock enables the photographer to set the exposure for a critical area in the scene.

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 wider 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 lens diaphragm. Aperture is expressed in f-numbers such as f/8, f/5.6, and so on.

artifact

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