AE (Autoexposure)

General-purpose shooting modes where the camera automatically sets the aperture and shutter speeds using its metered reading. Along with Programmed AE, Shutter Priority and Aperture Priority modes are also considered AE exposure modes and on some cameras, the ISO settings can be automatically set as well.

AE/AF lock

A camera setting that allows you to lock the current exposure and/or autofocus setting prior to taking a photo. This button lets you recompose the scene without holding the Shutter Release button halfway down.

AF-assist illuminator

In low-light and low-contrast shooting situations, this feature automatically adds light to the scene to aid the camera's autofocusing system. Some cameras have a dedicated lamp that shines; others use the pop-up flash, which emits a burst of very high frequency light pulses, and some dedicated speedlights project a lighted grid onto the scene.

ambient light

The light that naturally exists in the scene, which can be truly natural (sunlight) or artificial (everyday light fixtures in the room).


Also referred to as the diaphragm or f-stop setting of the lens. The aperture controls the amount of light allowed to enter through the camera lens. The higher the f-stop number setting, the smaller the aperture opening on the lens. Changing the aperture in whole stops doubles or halves the light entering the camera. Larger f-stop settings are selected by lower numbers, such as f/2 or f/1.2. The wider the aperture, the less ...

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