| 摘要 |
A zoom lens with a high variable power ratio including wide-angle lens capability, comprises, in order from the object, a first lens unit having a positive focal length, a second lens unit having a negative focal length, and a third lens unit having a positive focal lenth. The first, second and third lens units are mechanically movable to change the overall focal length and keep an image plane constant. The third lens unit is composed of, in order from the object, a third sub-lens unit a having a positive lens, a negative lens and a positive lens in order from the object and a third sub-lens unit b having a positive lens, a negative lens and a positive lens in order from the object.
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