Patent ID: 8238737

Claim:
An image pickup apparatus comprising: a lens barrel adapted to change a focal length by moving at least one of a first lens group and a second lens group in an optical axis direction, to increase a barrel length under a shooting condition, and to decrease the barrel length under a retracted condition, comprising: a first holding frame adapted to hold the first lens group; a second holding frame adapted to hold the second lens group; a light-amount adjusting member adapted to adjust an amount of light that transmits an optical system by changing a diameter of an aperture, said light-amount adjusting member being located between said first lens group and said second lens group; a third holding frame adapted to hold said light-amount adjusting member; and a cam mechanism adapted to move said first, second, and third holding frames in the optical axis direction so that a part of the second lens group is inserted into the aperture of said light-amount adjusting member and concave and convex surfaces, which are faced to each other, of the first and second lens groups are overlapped in the optical axis direction under the retracted condition, a control unit adapted to control said light-amount adjusting member to a super-full aperture condition so as to enlarge the diameter of the aperture up to the maximum diameter under the shooting condition and to control said cam mechanism so as to move said first, second, and third holding frames in the optical axis direction, when said lens barrel shifting to the retracted condition from the shooting condition.