Patent ID: 7106520

Claim:
A wide-angle zoom lens system comprising a negative first lens group, a positive second lens group, a negative third lens group, and a positive fourth lens group, in this order from an object; wherein upon zooming from the short focal length extremity to the long focal length extremity, the distance between said negative first lens group and said positive second lens group decreases, the distance between said positive second lens group and said negative third lens group increases, and the distance between said negative third lens group and said positive fourth lens group decreases; wherein said positive second lens group, said negative third lens group and said positive fourth lens group are arranged to move toward said object; and wherein said wide-angle zoom lens system satisfies the following conditions: 1.2 <|f (i=1) /f W |<2.0 1.5 <f (i=2) /f W <2.2 2.5 <|f (i=3) /f W |<3.6 3.2 <f (i=4) /f W <4.7 wherein fi designates the focal length (f 1 <0, f 3 <0) of the i th lens group (i=1˜4); and f W designates the focal length of the entire the wide-angle zoom lens system at the short focal length extremity.