| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens that has a large aperture ratio and offers high optical performance over an entire zoom range.SOLUTION: A zoom lens comprises, in order from the object side to the image side, first, second, and third lens groups having positive, negative, and positive refractive power, respectively, an aperture stop, an intermediate group, and a final lens group, where distance between each pair of adjacent lens groups changes while zooming and where the third lens group includes two or more positive lenses and one or more negative lenses. A composite focal length f12t of the first and second lens groups at the telephoto end, a focal length fn of a lens group N having a largest absolute value of negative refractive power amongst lens groups constituting the intermediate group, a focal length f3 of the third lens group, and a focal length ft of the entire system at the telephoto end are set appropriately.SELECTED DRAWING: Figure 1 |
