Adobe RGB

A color space created by Adobe to more closely match the output of inkjet printing devices. See also color space and sRGB.

AE lock

Pressing the camera's AE lock button locks the current exposure and lets you recompose the scene without changing the exposure.

AF (auto focus) lock

The focus can be locked either by pressing the Shutter Release button halfway down when the focus is locked, the camera can be moved, but the focus does not move. The focus stays locked until the shutter is released or the Shutter Release button is pressed. This allows the scene to be recomposed without changing the focus.

ambient light

The natural light in the scene, also referred to as available light.

angle of view

The amount of the scene in front of the camera that a specific lens sees.


The lens opening that the light passes through before reaching the sensor in the camera. The aperture can be adjusted by controlling the diaphragm by changing the f-stop. This is expressed as f/number — for example, f/5.6.

Aperture priority mode

In this mode, the photographer sets the aperture and the camera sets the shutter speed.

artificial light

Any light that the photographer introduces into a scene.


The camera automatically adjusts the focus depending on which focus sensor is selected. The autofocus on most dSLRs is started by pressing the Shutter Release button halfway down.

autofocus illuminator

A built-in light that illuminates the scene, helping the camera achieve focus when not enough ambient ...

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