A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Abstract - In the photographic sense, an image that is conceived apart from concrete reality, generally emphasizing lines, colors and geometrical forms, and their relationship to one another.

Accessory shoe - A fitting on top of the camera that incor­porates one or more electrical contacts for linking the camera to the flash. The most basic accessory shoe has one contact, which synchronizes the firing of the flash with the firing of the shutter, On more advanced cameras there may be as many as five contacts, which pass information, such as exposure readings, between the camera and dedicated flash units. The term "hot shoe" is sometimes used as an alternative to accessory shoe.

Angle of view - The angle over which a lens accepts light or "sees" a subject. The longer the focal length of a lens, the narrower its angle of view will be.

Aperture - The opening in a lens that admits light. Except in very simple cameras, the aperture can be varied in size by a diaphragm, which regulates the amount of light passing through the lens.

ASA see FlLM SPEED

Artificial light - Any light source used in photography other than that from natural sources (usually the sun). Generally the term refers to light specially set up by the photographer such as flash or photo-lamps. Photographic emulsions have different sensitivity to daylight and artificial light, and films maybe rated for either type.

Auto bracketing - A system that automatically makes a series of exposures at different exposure settings when the shutter is released, to increase the chances of obtaining a correctly exposed image.

Automatic exposure - A system that automatically sets correct exposure by linking a camera's exposure meter with the shutter or aperture or both. There are three main types: aper­ture priority, when the photographer sets the aperture and the camera selects the appropriate speed; shutter priority, when the photographer chooses the speed and the camera sets the correct aperture; and programmed, when the camera sets both aperture and shutter speed. Aperture priority is advantageous when you want to control depth of field; shutter priority comes into its own par­ticularly in action photography: and pro­grammed exposure can be useful when the photographer has to react quickly.

Automatic focusing - A camera system that automatically brings the lens into sharp focus on the subject. Auto focus systems operate very quickly and reliably, and can usually focus more rapidly than the photographer can un­aided, However, there are instances when manual focusing is preferable to automatic; for example, few auto focus systems can cope adequately when the subject is behind bars, such as animals in a zoo.

Available light - The existing light (natural or artificial) in any situation, without the introduction of supplementary light (for example, flash) by the photographer. The term usually refers to low light levels, for example indoors or at dusk