Automatic focusing system and incorporation within cameras.

摘要

An automatic focusing device employs an active range finder (11) to establish an initial range to an object (16). A blur is calculated based on the initial range. If the blur is less than a predetermined value, the active range finder (11) is bypassed in favor of a passive range finder (12). A focusing drive (31) is responsive to the output of the passive range finder (12) to drive the focus toward zero blur. If the initial range provides a blur calculation exceeding the predetermined value, the focusing drive (31) responds to the active range finder (11) until the calculated blur is reduced to a second predetermined value, at which time the active range finder (11) is bypassed in favor of the passive range finder (12). Thereafter, the focusing drive (31) responds to the passive range finder (12). <IMAGE>