Focus detection device, photographic lens unit, image-capturing apparatus and camera system

摘要: A focus detection device includes: a unit that includes pair of light-receiving element arrays and lens systems via which light fluxes are each guided to one the arrays, detects an image shift amount based upon output signals from arrays; acquisition obtains plurality sets opening data pertaining sizes positions openings; function value calculation calculates, data, gravitational center distance between centers overlapping areas where specific pupils overlap exit pupil; conversion converts defocus value.