Ability of a lens and camera to focus automatically on an object within its focusing sensors.

The ability of the camera and lens to keep the subject in focus during an exposure. Autofocus can be Continuous, meaning focus is maintained regardless of where it moves within the frame, or Single, m [..]

A system of sensors and motors that allow lenses to obtain focus automatically; in some cameras, the system also allows the lens to maintain focus on a moving subject. Read articles that include this [..]

A lens system that automatically focuses before the exposure is made. 

(n) an optical device for focussing a camera or other instrument automatically

A facility in which a camera or camcorder automatically finds the best possible focus for the image.

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 [..]

A function that allows the camera to set focus automatically. Sometimes abbreviated “AF”.

The camera uses an infrared beam or the subject's contrast to measure the camera to subject distance and focuses the lens automatically

Automatic focusing.

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 [..]

A system of sensors and motors that allow lenses to obtain focus automatically; in some cameras, the system also allows the lens to maintain focus on a moving subject. Read articles that include this [..]

The ability of a camera to focus on a subject electronically, rather than the photographer having to focus the lens manually.  

Autofocus is the ability of the lens to remain in focus during zoom-in, zoom-out, and motion functions.

System by which the camera lens automatically focuses the image of aselected part of the picture subject. AF-I & AF-S lenses:

A setting (or the default on most point and shoots) that means the camera chooses what to focus on, usually based on how the photographer composes the shot. Kind of like magic.

device used in certain cameras, projectors and enlargers that focuses the image automatically.

The ability of the camera and lens to keep the subject in focus during the exposure. Autofocus can be Continuous, meaning focus is maintained regardless of where it moves within the frame, or Single, meaning the point of focus is locked regardless of where the subject may move.

(electronics) A feature of some cameras and other optical systems that allows a correct focus on the subject to be obtained automatically ''This camera has autofocus, so it's more expensive.''