| 摘要 |
<p>A zoom-lens substantially consists of a positive-first-lens-group, fixed during magnification-change, a negative-second-lens-group, which moves from object-side toward image-side during magnification change from wide-angle-end to telephoto-end, a negative-third-lens-group, which corrects movement of an image-plane during magnification-change, and a positive-fourth-lens-group, which is fixed during magnification-change and includes a stop, in this order from object-side. The first-lens-group substantially consists of a negative-1a-th-lens-group, fixed during focusing, a positive-1b-th-lens-group, which moves during focusing, and a positive-1c-th-lens-group, fixed during focusing, in this order from object-side. The second-lens-group substantially consists of a negative-2a-th-lens-group and a positive-2b-th-lens-group, and a distance therebetween is changed during magnification-change. The third-lens-group moves in such a manner that a distance from the fourth-lens-group at telephoto-end is narrower than a distance from the fourth-lens-group at wide-angle-end. Predetermined conditional-formulas about a length from a most-object-side surface in the first-lens-group to the stop, a focal-length at wide-angle-end and a focal-length of the 1b-th-lens-group are satisfied.</p> |
