Patent ID: 6108136
Filing Date: 2000-08-22
Classification: G02B

Abstract:
A wide-angle zoom lens system comprising, in order from an object side thereof:a first lens group having negative refracting power;a second lens group;a third lens group having negative refracting power; anda fifth lens group,wherein, to zoom from a wide-angle end of said lens system to a telephoto end of said lens system, said first lens group moves nonlinearly and said second lens group, said third lens group, said fourth lens group and said fifth lens group move toward said object side,said lens groups move such that a spacing between said first lens group and said second lens group, a spacing between said second lens group and said third lens group, and a spacing between said fourth lens group and said fifth lens group become narrow while a spacing between said third lens group and said fourth lens group becomes wide,an aspherical surface is used in at least said first lens group, andsaid system satisfies the following conditions (1) and (4):0.7<.vertline.f.sub.1 /f.sub.w .vertline.<3 (1)3<.vertline.f.sub.5 .vertline./f.sub.w <8 (4)where f.sub.1 is a focal length of said first lens group, f.sub.5 is a focal length of said fifth lens group, and f.sub.w is a focal length of said zoom lens system at said wide-angle end.