Patent ID: 6268966
Filing Date: 2001-07-31
Classification: G02B

Abstract:
A zoom lens system comprising, in order from an object side:a positive first lens group that is movable along an optical axis for zooming, said positive first lens group including a negative first lens unit and a positive second lens unit that are arranged from said object side; anda negative second lens group that is movable along said optical axis for zooming;wherein each of said first and second lens units of said first lens group includes at least one negative lens, andwherein the following conditions (1), (2), (3) and (4) are satisfied,-3.1<f.sub.t /f.sub.1a <-2.5 (1)5.8<f.sub.t /f.sub.1b <7.0 (2)1.85<n.sub.1an (3)1.85<n.sub.1bn (4)wheref.sub.t is the longest focal length of the entire system,f.sub.1a is a focal length of the first lens unit;f.sub.1b is a focal length of the second lens unit;n.sub.1an is a refractive index of the negative lens in said first lens unit; andn.sub.1bn is a refractive index of the negative lens in the second lens unit.