Any light not directly produced by the sun. Can be tungsten, flash, household bulbs, sodium vapor street lamps, etc. In many cases, the color produced by artificial light is deficient in the blue end of the spectrum, thus daylight-balanced color films will record the light as being warm/red/amber. Tungsten-balanced slide films, or color-balancing f [..]

 A

The maximum angle a lens covers in the field. Measured in degrees, and qualified by terms such as wide-angle, normal, and telephoto. A wide angle lens has a wider angle of view than a telephoto lens. A 135mm lens on a 35mm SLR covers an 18-degree angle of view; a 28mm lens covers a 75-degree angle of view.

The opening of a lens, the size of which is controlled by a diaphragm. The term is commonly used to designate f-stops, such as f/4, f/5.6 etc., which are actually arrived at by dividing the focal length of the lens by the diameter of the aperture. Thus, f/11 on a 110mm focal length lens means the opening is 10mm. The wider the opening, the lower th [..]

An autoexposure mode in which the aperture is selected and the exposure system selects the appropriate shutter speed for a correct exposure. Sometimes referred to as AV or simply A on exposure mode controls.

Long-lasting. In processing, those procedures that help insure stability of the image. Also, storage materials that will not damage photographic film and paper, or computer-produced prints.

A method of exposure where aperture and shutter speed settings are first read, then set, by the camera's exposure system. Various autoexposure modes allow for customization or biasing the readings.

A push-button, switch, or lever that locks in exposure after the initial reading has been made, regardless of a change in camera position or light conditions after the lock is activated. Release of the lock button returns the exposure system to normal. Useful for making highlight or shadow readings of select portions of the frame, and an essential [..]

A method of focusing where focusing distances are set automatically. In 35mm SLRs, a passive phase detection system that compares contrast and edge of subjects within the confines of the autofocus brackets in the viewfinder and automatically sets focusing distance on the lens. Autofocusing motors may be in the camera body or the lens itself. Active [..]

An add-on optical device that alters the focal length of the prime lens for close-up, telephoto, or other special effects photography. The close-up devices, for example, usually comes in +1, +2, and +3 powers; the higher the number the greater the magnification.