Patent ID: 8199417

Claim:
A zoom lens comprising: a zoom optical system including movable lens groups for zooming which are moved between a ready-to-photograph position in a zooming range and an accommodated position behind said ready-to-photograph position in an optical axis direction, one of said movable lens groups serving as an aperture-control lens group; a variable aperture-stop mechanism which is positioned one of in front of and behind said aperture-control lens group and is movable relative to said aperture-control lens group in said optical axis direction, said variable aperture-stop mechanism including a plurality of aperture blades, a base member which supports said plurality of aperture blades so as to allow each of said plurality of aperture blades to rotate freely, and an opening/closing ring which rotates relative to said base member, forward and reverse rotations of said opening/closing ring causing said plurality of aperture blades to rotate to thereby vary a size of an adjustable aperture formed by said plurality of aperture blades; a first rotation imparting member, which rotates said opening/closing ring by a relative movement between said variable aperture-stop mechanism and said first rotation imparting member in said optical axis direction so as to hold said adjustable aperture at a small aperture size when said aperture-control lens group moves in said optical axis direction between a wide-angle extremity position thereof and a position in a vicinity of said wide-angle extremity position in said zooming range; and a second rotation imparting member, which rotates said opening/closing ring by a relative movement between said variable aperture-stop mechanism and said second rotation imparting member in said optical axis direction so as to open and hold said adjustable aperture at a large aperture size when said aperture-control lens group moves in said optical axis direction from said wide-angle extremity position in said optical axis direction to said accommodated position, wherein said aperture-control lens group is partly positioned in said adjustable aperture held at said large aperture size when said aperture-control lens group is positioned in said accommodated position.