Patent ID: 7253966

Claim:
A zoom lens system comprises a negative first lens group, a variable diaphragm, a positive second lens group, in this order from an object, wherein zooming is performed by moving said negative first lens group and said positive second lens group; wherein said negative first lens group comprises at least two negative lens elements and at least two positive lens elements; and wherein said zoom lens system satisfies the following conditions: 1.5 <|f 1/ fw|< 1.8 1.0 <f 2/( fw×ft ) 1/2 <1.3 1.0 <|f 2/ f 1|<1.2 wherein f1 designates the focal length of said negative first lens group; f2 designates the focal length of said positive second 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.