Study Guide 4

The Curves adjustment

lets you adjust points throughout the tonal range of an image (from shadows to highlights).

Levels adjustment

corrects the tonal range and color balance of an image by adjusting intensity levels of image shadows, midtones, and highlights.

A histogram

illustrates how pixels in an image are distributed by graphing the number of pixels at each color intensity level.

The Image Rotation

commands let you rotate or flip an entire image.

Keystone distortion

occurs when an object is photographed from an angle rather than from a straight-on view.

Cropping

is the process of removing portions of an image to create focus or strengthen the composition.

Chromatic aberration

is caused by the failure of the lens to focus different colors to the same spot.

Pincushion distortion

causes straight lines to appear to bend inward.

Barrel distortion

causes straight lines to appear to bow outward.

Vignetting

causes the edges, especially the corners, of an image to be darker than the center.

Camera lenses

can exhibit different types of defects at certain focal lengths, f-stops, and focus distances.