Patent ID: 7092169
Filing Date: 2006-08-15
Classification: G02B

Abstract:
1. A zoom lens system, in sequence from an object side to an image side, comprising: a first lens group having positive refractive power and being fixed for gathering incoming light; a second lens group having negative refractive power for changing a focal length of the zoom lens system; a third lens group having positive refractive power and being made stationary; a fourth lens group having positive refractive power and being movable for eliminating for an optical aberration of the zoom lens system; and a fifth lens group having positive refractive power and being movable for focusing purpose; wherein, during zooming from a wide-angle end to a telephoto end, said second and fourth lens groups are moved independently toward the third lens group in such a manner that a spacing between said first lens group and said second lens group increases and a spacing between said third lens group and said fourth lens group decreases; wherein, the relationship between the fourth lens group and the second lens group satisfies the following condition: