Patent ID: 8014660
Filing Date: 2011-09-06
Classification: G02B,G03B

Abstract:
1. 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; and a variable aperture-stop mechanism, wherein one of said movable lens groups serves as an aperture-control lens group, wherein said variable aperture-stop mechanism 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, wherein said variable aperture-stop mechanism includes an aperture blade opening/closing mechanism which includes at least one movable aperture blade which forms an adjustable aperture and varies a size of said adjustable aperture at least between a large size and a small size by moving said movable aperture blade, wherein said variable aperture-stop mechanism includes a fixed circular aperture which is smaller in aperture size than said large-sized adjustable aperture and greater in aperture size than said small-sized adjustable aperture, wherein said movable aperture blade and said fixed circular aperture are positioned in that order from the aperture-control lens group side, and wherein, when said movable lens groups are moved to said accommodated position thereof, said aperture blade opening/closing mechanism varies said size of said adjustable aperture to said large size while said variable aperture-stop mechanism is moved to a close position to said aperture-control lens group, so that at least part of said aperture-control lens group enters said large-size adjustable aperture.