Patent ID: 6480340
Filing Date: 2002-11-12
Classification: G02B

Abstract:
A zoom lens comprising in order from a large conjugate side to a small conjugate side a negative power first lens group movable in its entirety along an optical axis during focusing and, however, stationary during zooming, a positive power second lens group, a positive power third lens group, a negative power fourth lens group, and a stationary positive power fifth lens group, said second to said fourth lens groups being movable along an optical axis of the zoom lens in a given relationship relative to one another and relative to said first and fifth lens groups during zooming to continuously vary a magnification and compensate a shift of image plane, said zoom lens satisfying the following conditions:âˆ’1.71/F0.72/F<2.2 1.55/F<2.2 whereF is the overall focal length of the zoom lens at a wide angle end; F1 is the focal length of the first lens group; F2 is the focal length of the second lens group; F5 is the focal length of the fifth lens group; and wherein the first and second lens group are arranged without any intervening lens element.