Patent ID: 6924939
Filing Date: 2005-08-02
Classification: G02B

Abstract:
1. A zoom lens system comprising, in order from an object side to an image side: a first lens unit having negative optical power; a second lens unit having positive optical power, said second lens unit consisting of, in order from the object side to the image side, a first positive lens element having an aspherical surface, and a cemented lens formed by cementing a second positive lens element and a negative lens element having an aspherical surface; and a third lens unit having positive optical power; wherein during zooming operation of said zoom lens system, a distance between said first lens unit and said second lens unit is smaller at a telephoto end than at a wide-angle end, and a distance between said second lens unit and said third lens unit is changed, and during zooming operation of said zoom lens system from the wide-angle end to the telephoto end, said second lens unit is moved toward the object side.