US Patent 7477313 Light-quantity adjusting apparatus, optical apparatus, and camera

A light-quantity adjusting apparatus which can temporarily suppress an MTF (contrast) from being deteriorated by small-aperture diffraction is disclosed. The light-quantity adjusting apparatus comprises a main body in which an opening is formed, a light-blocking member moved with respect to the opening to change an area of a light-passing aperture, an optical filter moved with respect to the opening to insert and remove with respect to a region opposed the light-passing aperture, an actuator serving as a drive source, a drive mechanism for driving the light-blocking member and the optical filter by drive force from the actuator.