| 摘要 |
A zoom lens includes a first lens unit with positive refraction that is stationary for zooming, a second unit with negative refraction that moves during zooming, a third unit that moves on the optical axis along with movement of the second unit, and a fourth unit with positive refraction that is stationary during zooming, arranged in order from the object to image planes. The first unit includes a negative meniscus element G1 convex towards the object plane, a positive element G2, a positive element G3, and a positive meniscus element G5 convex towards the object plane, arranged in order from the object to image planes. The respective curvature radii G1R1, G1R2, G5R1, and G5R2 of surfaces of the elements G1 and G5 and the respective focal lengths fG1, fG2, and f1 of the elements G1 and G5 and the first unit are set appropriately. |
