Patent ID: 6917476

Claim:
A zoom lens system comprising a negative first lens group, a positive second lens group, and a positive third lens group having a positive lens element, 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; said negative first lens group comprises a negative lens element and a positive lens element, in this order from said object; said positive second lens group comprises a positive lens element and a negative lens element, in this order from said object; said positive second lens group satisfies the condition: νs<23 said zoom lens system satisfies the following conditions: 0.4<( fw·ft ) 1/2 /|f 1|<0.8 ( f 1<0) 0.7<( fw·ft ) 1/2 /f 2<1.4 0.4<( fw·ft ) 1/2 /f 3<0.9 wherein fw designates the focal length of the entire zoom lens system at the short focal length extremity; ft designates the focal length of the entire zoom lens system at the long focal length extremity; fi designates the focal length of the ith lens group (i=1˜3); and νs designates the Abbe number of the most image-side negative lens element in said positive second lens group.