Ghost reducing device with multiple diaphragm blades for blocking light for reducing ghost, imaging device provided therewith, ghost reducing method, and imaging optical system

A ghost reducing method, comprising:

• driving multiple diaphragm blades to form at least one opening to let light pass through, the multiple diaphragm blades being disposed in a vicinity of a pupil position in an imaging optical system,
• driving the diaphragm blades to adjust a size and/or a position of the at least one opening so that the at least one opening does not overlap an optical axis of the imaging optical system, and to block totally a symmetrical position to the at last one opening with respect to the optical axis of the imaging optical system.

An imaging optical system that forms an image of light from a subject through a lens onto an imaging element, comprising:

• multiple diaphragm blades that form at least one opening to let the light pass through and that are disposed in a vicinity of a pupil position in the imaging optical system, and when reducing ghosts, adjust a size and/or a position of the at least one opening so that the at least one opening does not overlap an optical axis of the imaging optical system, and block the light totally in a symmetrical position to the at least one opening with respect to the optical axis of the imaging optical system.