Automatic focusing apparatus and method

摘要

An automatic focusing apparatus moves a focusing lens once over a full movement range from the nearest point or from the infinite point so as to cause a photoelectric detector to output an electrical signal at predetermined stepwise lens positions. A lens position range can be specified based on the output electrical signal. The lens position range contains a lens position allowing the maximum focus evaluation value. A lens position for the maximum evaluation value is searched within the lens position range. A reliable and fast focusing operation can be obtained for finding out the maximum focus evaluation value without the effect of a local extremum in the focus evaluation value. <IMAGE> <IMAGE>