| 摘要 |
A zoom lens includes, in order from the object side, a first lens unit with negative power, a second lens unit with positive power, a third lens unit with positive power, and a fourth lens unit. When the magnification of the zoom lens is changed in the range from a wide-angle position to a telephoto position, spacing between the first lens unit and the second lens unit is narrowed and spacing between the second lens unit and the third lens unit is widened. An aperture stop moved integrally with the second lens unit is interposed between the most image-side lens element of the first lens unit and the most image-side lens element of the second lens unit. The first lens unit has, in order from the object side, a negative lens element and a positive lens element and satisfies the following conditions: 0.15<&phgr;1MF/&phgr;1MR<1.0 −3.0<&phgr;1PF/&phgr;1PR<−1.0 where &phgr;1MF is the power of the object-side surface of the negative lens element, &phgr;1MR is the power of the image-side surface of the negative lens element, &phgr;1PF is the power of the object-side surface of the positive lens element, and &phgr;1PR is the power of the image-side surface of the positive lens element.
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