| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which offers a high zoom ratio, is well corrected for chromatic aberration over an entire zoom range from the wide-angle end to the telephoto end, and provides superior optical performance over the entire zoom range.SOLUTION: A zoom lens comprises a first lens group, a second lens group, a third lens group, an aperture stop, and a fourth lens group arranged in order from an object side to an image side. A partial dispersion ratio &thetas;Lm of a material of a positive lens Lm made of a material having the highest partial dispersion ratio in a rear group, a distance d from the aperture stop to an image plane, a distance dLm from the aperture stop to the positive lens Lm, an average Abbe number &ngr;Rfp and an average partial dispersion ratio &thetas;Rfp of materials of positive lenses in a front group, and an average Abbe number &ngr;Rfn and an average partial dispersion ratio &thetas;Rfn of materials of negative lenses in the front group are each appropriately set. |
