Patent ID: 7961402

Claim:
A high zoom-ratio zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a positive fifth lens group, and a negative sixth 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 positive first lens group and said negative second lens group increases, and a distance between said negative second lens group and said positive third lens group decreases; wherein said high zoom-ratio zoom lens system satisfies the following conditions: 5.0 <f 1 /|f 2<9.0( f 2<0) 4.1 <f 1 /f 5<6.0 wherein f 1 designate the focal length of said positive first lens group; f 2 designate the focal length of said negative second lens group; and f 5 designate the focal length of said positive fifth lens group.