Patent ID: 7460312

Claim:
A zoom lens system comprises a negative first lens group, a positive second lens group and a positive third lens group functioning as a focusing 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, and the distance between said positive second lens group and said positive third lens group increases; wherein said positive third lens group comprises cemented lens elements having a positive lens element and a negative lens element arranged in this order from the object; and wherein said zoom lens system satisfies the following condition: 0.2 <f 3−p /|f 3−n |<0.35 wherein f 3−p designates the focal length of said positive lens element of said positive third lens group; and f 3−n designates the focal length of said negative lens element of said positive third lens group.