Focal point detection apparatus and focal point detection module

摘要

A sub-mirror which deflects a focal point detection light flux passing through an area off the optical axis of a photographing optical system toward the optical axis and a second deflection member that deflects the focal point detection light flux deflected by the sub-mirror to allow it to advance roughly parallel to the photographic optical axis are provided. A pair of light fluxes achieved by deflecting the focal point detection light flux twice are guided to an image sensor to form a pair of subject images on the image sensor. The focal adjustment state is detected based upon the extent to which the pair of subject images are offset.