| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens having excellent optical performance in the entire zoom area and a large diameter.SOLUTION: A zoom lens comprises a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. When zooming from a wide angle end to a telephoto end is performed, the first lens group is moved to an object side, so as to reduce the interval between the first lens group and the second lens group and increase the interval between the third lens group and the fourth lens group. In the zoom lens, the third lens group comprises a single lens or a single cemented lens. The zoom lens satisfies the following conditional expressions (a) and (b): &Dgr;m3/(fw×ft)1/2<0.3 (a) d23_max/(fw×ft)1/2<0.5 (b), where &Dgr;m3 is the fluctuation amount of the interval between the second lens group and the third lens group when magnification is varied, fw is a focal length at the wide angle end, ft is a focal length at the telephoto end, and d23_max is the maximum value of the interval between the second lens group and the third lens group when magnification is varied. |
