Patent ID: 7860385

Claim:
An autofocus system comprising: an imaging unit that takes a subject image formed by an optical system; an autofocus unit that performs autofocus adjustment that adjusts focus of the optical system so as to bring into focus a subject in an AF area in a shot image taken by the imaging unit; a tracking unit that moves the AF area in accordance with movement of a tracking target subject in the image taken by the imaging unit; a pattern registration unit that registers a registration pattern of at least one subject among subjects in the image taken by the imaging unit; a tracking target detection unit that detects the at least one registration pattern, which is registered in the pattern registration unit, from among subjects in the image taken by the imaging unit; and a tracking target selection unit that selects a registration pattern to be tracked, from among the at least one registration pattern registered in the pattern registration unit, wherein when the tracking target detection unit detects that the tracking target subject disappears from the image in the course of tracking the tracking target subject having the registration pattern selected by the tracking target selection unit, the autofocus adjustment of the autofocus unit is disabled, and thereafter a disable state of the autofocus adjustment is maintained even if the tracking target detection unit detects that a subject having any of the at least one registration pattern registered in the pattern registration unit appears in the image.