Autofocus

An autofocus (or AF) optical system uses a sensor, a control system and a motor to focus fully automatic or on a manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. The methods are named by the used sensor: Active, passive and hybrid.

Read more about Autofocus:  General, History, Active, Passive, Hybrid Autofocus, Comparison of Active and Passive Systems, Trap Focus

Other articles related to "autofocus":

F90x
... At the time of its release it was noted for its fast autofocus speed compared to previous Nikon models, which had lagged behind competitor Canon's ... F4, the professional model available at the time of the F90's release, had very slow autofocus compared to Canon's autofocus SLRs ... The Nikon F90's autofocus system was driven by a small 'peanut' motor in the camera body that drove the lens via a mechanical link, unlike Canon's autofocus system, which used motors built into each ...
Autofocus - Trap Focus - AI Servo
... AI servo is an auto focus mode found on Canon SLR cameras, although the same principle is used with Nikon and some Pentax cameras, known there as "continuous focus" (AF-C) ... Also referred to as focus tracking, it is used to track a subject as it moves around the frame, or toward and away from the camera ...
Canon T80 - Autofocus
... The autofocus system in the T80 works in the same manner as the focus assist system built into the earlier AL-1 ... The autofocus lenses contained a motor, and electrical contacts in the lens mount connected this motor to the camera's circuits ...
Speedlite EX - Speedlite Products - 400 Series Flashes - 420 EX
... Compared to its predecessor, the 380EX, it provided slightly more power, an improved autofocus assist beam, tilt and swivel (the 380EX could only tilt), and the ability to serve as a slave in Canon's wireless ... Its autofocus assist system was designed to cover Canon's autofocus layouts with between 1 and 7 autofocus points it was not designed to cover the 45-point autofocus layout used by higher-end bodies ... to project horizontal and vertical patterns, which matched the line sensitivity of the autofocus sensors used in those autofocus layouts ...
Chinon CE-5 - Specifications
3 autofocus pins were present upon the top-left of the mount, which the autofocus lenses interfaced with ... These autofocus lenses were rather heavy and depended upon their own large, lens-mounted motors ...