Patent ID: 6829106
Filing Date: 2004-12-07
Classification: G02B

Abstract:
A high-zoom-ratio zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group, and a negative fourth lens group, in this order from an object,wherein zooming is performed by moving each of said positive first through positive fourth lens groups along the optical axis; and wherein said high zoom-ratio zoom lens system satisfies the following conditions: 0.223W/fW<0.70 0.0223/fW<0.2 11T/f2|<14 (f2<0) 12T/f3<15 wherein LD23W designates the distance from the most object-side surface of said negative second lens group to the most image-side surface of said positive third lens group, at the short focal length extremity; &Dgr;D23 designates the difference in the distance between said negative second lens group and said positive third lens group at the short focal length extremity and the distance between said negative second lens group and said positive third lens group at the long focal length extremity; f2 designates the focal length of said negative second lens group; f3 designates the focal length of said positive third lens group; fW designates the focal length of the entire the zoom lens system at the short focal length extremity; and fT designates the focal length of the entire the zoom lens system at the long focal length extremity.