The light-sensitive cell on a digital image sensor, it records one intensity and one colour value. Information from several photosites is required to create a pixel in the image.

Button controls on a camera that allow photographers to lock the exposure on a different part of the subject from the point of focus - or vice versa. In most cameras, pressing the shutter button halfw [..]

The light that exists in a specific situation without augmentation with flash or studio lights. Also known as 'available light'.

The opening in the iris diaphragm of a lens that allows light to pass through the lens to the image sensor.

Usually denoted by the A (or Av) setting on a camera's mode dial, this shooting mode allows the photographer to set a specific aperture value while the camera will adjust the shutter speed automa [..]

A term originally developed for the 'Advanced Photo System' film format but now used to define a digital imaging sensor size that measures between 21.5 x 14.4 mm and 23.7 x 15.7 mm in area.

Preserving digital images in a way that is independent of where these records are kept. Image archives can consist of prints or copies on optical disk or hard disk drive.

Undesirable visual defects produced by digital imaging systems. They can be generated by either input or output devices and include noise, colour casts, distortions and lost information. All degrade i [..]

The relationship between the horizontal and vertical dimensions of an image. The horizontal dimension is normally quoted first. A 35mm film frame has an aspect ratio of 3:2, as do most DSLR cameras. I [..]

A camera control that focuses the lens on the subject. Two types of AF are in common use, active infrared (IR) and passive contrast-based. The former fires a beam of infrared light at the subject and [..]