Patent ID: 6055114
Filing Date: 2000-04-25
Classification: G02B

Abstract:
A zoom lens capable of forming an image of an object and zooming between a maximum wide-angle state and a maximum telephoto state, the zoom lens comprising objectwise to imagewise:a) a first lens group having overall positive refractive power;b) a second lens group having one or more surfaces each arranged along an optical axis and each with a paraxial curvature, said second lens group having overall negative refractive power and separated from said first lens group by a first air space;c) a third lens group having overall negative refractive power and separated from said second lens group by a second air space;d) a fourth lens group having overall positive refractive power and separated from said third lens group by a third air space;e) a fifth lens group having positive refractive power and separated from said fourth lens group by a fourth air space;f) wherein the zoom lens is designed such that when zooming from the maximum wide-angle state to the maximum telephoto state, at least said second lens group moves imagewise and at least one of said first lens group and said fourth lens group moves so as to increase said first air space, increase said second air space, decrease said third air space, and decrease said fourth air space; andg) wherein the following design condition is satisfied:0.1<(Ave. C).multidot.f.sub.w <0.6wherein, Ave. C is the average value of the absolute value of said paraxial curvature of each of said one or more lens surfaces comprising said second lens group, and f.sub.w is the focal length of the entire zoom lens in the maximum wide-angle state.