Focus detection device for objective lens

摘要

A focus detection function is disposed on the focal plane of an objective lens. The in-focus state of the objective lens is determined with respect to a plurality of range-finding regions in a photographic range by employing the focus detection function. A correction value of the objective lens corresponding to a predetermined range-finding region among the plurality of range-finding regions is already stored, thereby finding correction values corresponding to regions other than the predetermined region. As a result, focus detection with respect to the regions other than the predetermined region can be performed.