Filming & Production
Autofocus
Also called: AF, eye AF, face tracking
Solo shooting is where it earns its keep, since nobody is behind the camera to pull focus when you lean in or sit back. Modern systems detect a face, lock onto the nearest eye and hold it as the subject moves, and most bodies let you restrict tracking to the subject so a busy background cannot steal it.
It fails in predictable ways. Low light slows it down, a wide aperture leaves almost no margin for error, and hunting shows up as the image pulsing gently in and out across a take. Shots with objects passing between camera and subject are safer on manual focus with the distance marked.