Patent ID: 7443603

Claim:
A wide-angle zoom lens system comprises 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, a distance between said negative first lens group and said positive second lens group decreases, a distance between said positive second lens group and said negative third lens group increases, and a distance between said negative third lens group and said positive fourth lens group decreases; wherein said wide-angle zoom lens system satisfies the following conditions: 0.9< f 2 /ft< 1.2 2.9< f 4 /fw< 3.4 wherein f 2 designates the focal length of said positive second lens group; f 4 designates the focal length of said positive fourth lens group; ft designates the focal length of the entire wide-angle zoom lens system at the long focal length extremity; and fw designates the focal length of the entire wide-angle zoom lens system at the short focal length extremity.