Patent ID: 6781768
Filing Date: 2004-08-24
Classification: G02B

Abstract:
A zoom lens system comprising a negative first lens group, a positive second lens group, and a positive third lens group, in this order from an object,wherein upon zooming from the short focal length extremity to the long focal length extremity, said positive third lens group remains stationary, and said negative first lens group and said positive second lens group move along the optical axis of said zoom lens system; wherein said first lens group comprises at least one positive lens element having a convex aspherical surface facing toward an image; and wherein said zoom lens system satisfies the following conditions: 1.2f1/f2|<1.6 0.8<f3/f2<1.3 wherein f1 designates the focal length of said negative first lens group; f2 designates the focal length of said positive second lens group; and f3 designates the focal length of said positive third lens group.