| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens having a wide angle of view, a high zoom ratio, and further high optical performance over the entire zoom range.SOLUTION: The zoom lens comprises, in order from an object side to an image side, a positive first group which is immovable for varying power, a negative second group which is moved in varying power, a positive third group which is moved in varying power, a positive fourth group which is moved in varying power, and a positive fifth group which is immovable for varying power. Each of the first to fifth groups includes at least one positive lens and one negative lens. The zoom lens satisfies conditions of 10<&ngr;p-&ngr;n<54, -1<&bgr;2w<-0.05, -5<&bgr;2t<-1, and -1<&bgr;34z2<-0.3, where &ngr;p is the average Abbe number of the positive lens of the fourth group, &ngr;n is the average Abbe number of the negative lens of the fourth group, &bgr;2w is the imaging magnification of the second group at a wide angle end, &bgr;2t is the imaging magnification of the second group at a telephoto end, and &bgr;34z2 is the imaging magnification of a composite lens group comprising the third group and the fourth group in a zoom position z2 where the second group has imaging magnification -1. |
