- Continuous Servo AF is any autofocus system that focuses continuously to keep a moving subject (or moving photographer) in focus, as long as the shutter is partially depressed. If a photographer uses shutter button focus (this is the default way cameras are configured, where focus is attained when the shutter button is half-pressed) and their camera’s autofocus mode is set to Continuous Servo AF, whatever is located within the frame where the autofocus point or points are selected will be in focus, even if it moves.
This autofocus mode is useful for tracking moving subjects, and is also useful for focusing at very shallow depth (fast apertures) when shooting hand-held in very close-up situations. (Focusing on a bride's eyelashes using an f/1.4 aperture lens, for example)
Continuous Servo AF
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