An optical system to attain a clear image of an object when the object is photographed in a state where an optical axis of a lens is inclined relative to the object, includes a lens which refracts light radiating from the object, an image producing surface on which the image of the object is produced according to the light refracted by the lens, and an image producing surface control unit which controls the image producing surface to move with respect to the lens. The image producing surface control unit includes an angle control unit to control an angle between an optical axis of the lens and the image producing surface.