Patent ID: 7310192
Filing Date: 2007-12-18
Classification: G02B

Abstract:
1. A zoom lens comprising, going from an object side to an image plane side: a first lens group located on said object side of said zoom lens, said first lens group having an overall negative refractive power and further comprising, going from said object side to said image plane side: a second lens group located on said image plane side of said zoom lens, said second lens group having an overall positive refractive power; wherein said zoom lens includes only said first lens group and said second lens group between said object side and said image plane side of said zoom lens, and wherein zoom magnification is changed from a wide-angle end to a telephoto end by moving said first lens group toward said image plane side and then reversing to said object side, while moving said second lens group to said object side, said zoom lens meeting conditions (3), (4): where DG DG fw: focal length of said lens system at said wide-angle end from said first lens group to said image plane; fG fG