Glossary

A

Ambient Light

The natural light in a scene.

Aperture

The maximum size of the hole through which light enters the camera.

Artifact

Unwanted distortions in an image caused by image compression.

Aspect Ratio

The ratio between the width and height of an image.

B

Bit

The smallest unit of computer memory.

Bitmap

A method of storing information that maps an image pixel bit by bit.

Byte

A group of 8 bits, the basic unit of information for the computer.

C

Chromatic Aberration

A fringing effect around the edges, which is caused by the lens not focusing correctly.

Color Depth

The number of bits assigned to each pixel in the image and the number of colors that can be created from those bits.

D

Depth of Field

The distance between the nearest and farthest points that appear in sharp focus in a photograph.

Digital Zoom

A digital magnification of the center 50% of an image. Digital zooms increase the apparent image size by interpolation. They do not increase the amount of image information.

DPI

Dots per Inch. A measurement of the resolution of a digital photo or digital camera. The higher the number, the greater the resolution.

E

EXIF

Exchangeable Image File. This file format embeds camera and exposure information into the graphic file created by the camera.

Exposure

The length of time that the lens is open, allowing light to fall on the camera's image sensor.

F

F-stop

A numerical designation indicating the size of the aperture.

Flash Mode

The camera mode that determines how the internal flash is used in the photo.

Focal Length

The distance from a point where an image is formed (the focal point) to a point in or near the camera lens.