| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens system having four lens groups of negative, positive, negative and positive refractive power, the system utilizing the advantage that deterioration of performance in manufacturing process hardly occurs because its error sensitivity is low, and achieves excellent optical performance when a vibration-proof function is mounted.SOLUTION: The zoom lens system comprises: a negative first lens group G1; a positive second lens group G2; a negative third lens group G3; and a positive fourth lens group G4. When varying power from a wide angle end to a telephoto end, the distance between the first lens group and the second lens group decreases, the distance between the second lens group and the third lens group increases, and the distance between the third lens group and the fourth lens group decreases. The third lens group includes a cemented lens in which a positive lens and a negative lens are cemented. The zoom lens system satisfies the following conditional expressions (1) and (2): (1) -2.50<f1/f2<-1.57, and (2) f3/f3B<-0.1, where f1 is the focal distance of the first lens group, f2 is the focal distance of the second lens group, f3 is the focal distance of the third lens group, and f3B is the focal distance of the cemented surface of the cemented lens in the third lens group. |
