Patent ID: 7417800

Claim:
A zoom lens system comprising a negative first lens group, a positive second lens group, a positive third lens group and a positive fourth lens group, in this order from an object, wherein said negative first lens group further comprises a reflection member; wherein said first lens group remains stationary when zooming is performed from the short focal length extremity to the long focal length extremity; and wherein said zoom lens system satisfies the following conditions: 1.0 <f 2/( fw×ft ) 1/2 <1.5 1.2< |f 1 a|/fw< 1.8( f 1 a< 0) 2.0 <f 1 b/ft< 4.0 wherein f 2 designates the focal length of said positive second lens group; 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; f 1 a designates the combined focal length of an object-side lens element with respect to said reflection member in said negative first lens group; and f 1 b designates the combined focal length of image-side lens elements with respect to said reflection member in said negative first lens group.