Patent ID: 8120865

Claim:
An optical apparatus comprising: an aperture stop having an aperture variable in size; an ND filter movable with respect to the aperture of the aperture stop, the ND filter having a first part and a second part movable into and out of an optical path defined by the aperture stop, with the first part insertable into the optical path before the second part; an actuator that drives the ND filter; and a controller that controls the actuator, wherein the first part is sized to fully cover a first aperture of the aperture stop, which is narrower than a fully opened aperture thereof, but not fully cover the fully opened aperture, wherein the first part has a transmittance of 75% or more, wherein the second part is adjacent to the first part in a movement direction of the ND filter and has a transmittance of less than 75%, wherein, during video capturing, in any insertion operation of the ND filter from a further retracted position than a first position, which is a position where the first part is retracted with respect to the first aperture, toward a further inserted position than the first position, the controller determines whether the ND filter has reached the first position, and controls the actuator, when the controller determines that the ND filter has reached the first position, to move the ND filter without halting until the ND filter reaches a second position, which is a position where the first part fully covers the first aperture, and wherein, during video capturing, in any retraction operation of the ND filter from a further inserted position than the second position toward a further retracted position than the second position, the controller determines whether the ND filter has reached the second position, and controls the actuator, when the controller determines that the ND filter has reached the second position, to move the ND filter without halting until the ND filter reaches the first position.