Patent ID: 7773874
Filing Date: 2010-08-10
Classification: G02B,G03B

Abstract:
1. A focus detection method for detecting a focus state based on object images formed through a photographing optical system in at least one focus detection area, while performing a search operation in which a focusing lens group of said photographing optical system is moved from one toward the other of a near extremity and a far extremity, said focus detection method comprising: determining at least one support area which overlaps said focus detection area; determining a position of said focusing lens group at which an in-focus state is detected in said focus detection area to be an in-focus position of said focusing lens group when a brightness of said object is one of equal to and higher than a predetermined value; and determining a position of said focusing lens group at which said in-focus state is detected in said focus detection area to be the in-focus position, upon an in-focus state being detected both in said focus detection area and in said support area which overlaps said focus detection area when said brightness of said object is lower than said predetermined value.