Photo Glossary

Aberration

The inability of a lens to produce a perfect, sharp image, especially towards the edge of the lens field.

Absorption

Occurs when light is absorbed by a surface it hits and gets converted into heat waves.

Accessory shoe

Is the metal or plastic fitting on the top of the camera which supports accessories such as viewfinder, rangefinder, or flash gun.

Achromatic (lens)

A lens system designed to reduce chromatic aberration. It renders the same focal length for red and blue light wavelengths at the focal plane.

Acutance

A measure of the image sharpness.

Adjustable camera

A camera with manually adjustable settings for distance, lens openings, and shutter speeds.

Adjustable focus lens

A lens that has adjustable distance settings.

AF lock

A mode to lock the focus to a predetermined point. Useful when shooting a subject outside the focus area in the viewfinder. The photographer should first lock the focus with the subject inside the focus area, then recompose the shot as necessary.

AF sensor

The sensor used to detect and help correct the focus in cameras equipped with an autofocus function.

Ambient light

The available light completely surrounding a subject. Light already existing in an indoor or outdoor setting that is not caused by any illumination supplied by the photographer.

Andy Warhol

Andy Warhol (1928 – 1987) was an American artist. He created extremely simple and high-contrast color paintings. Media called him the Prince of Pop Art and a key figure in Pop Art. In the 1960s Andy Warhol created several mass-produced images from photographs of celebrities such as Marilyn Monroe, Elvis Presley, and Jackie Onassis.

Angle of view

Is the area of a scene that a lens covers or sees. Angle of view is determined by the focal length of the lens. A wide-angle lens (short-focal-length) includes more of the scene-a wider angle of view-than a normal (normal-focal-length) or telephoto (long-focal-length) lens.

Aperture

Is the circular hole in the front of the camera lens which controls the amount of light allowed to pass on to the film or on to the another sensor. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f-numbers - the larger the number, the smaller the lens opening.

Aperture priority

An exposure mode on a certain camera that lets you set the aperture while the camera sets the shutter speed for proper exposure. If you change the aperture, or the light level changes, the shutter speed changes automatically.

Artifact

The defects that appear in an image. Some of the common imaging artifacts: a blooming, a chromatic aberrations, a jaggies, a JPEG compression, a maze artifacts, a moire, a noise, a sharpening halos.

Artificial daylight

Is the artificial light having a similar color temperature to daylight.

Artificial light

Light not originating from a natural source. The commonest artificial light sources in photography are flash, and tungsten bulbs.

Aspect ratio

The ratio of width to height in photographic prints.

Autofocus (AF)

System by which the camera lens automatically focuses the image of a selected part of the picture subject.

Available light

The light present in an area without the addition of a strobe or a floodlight.