| 摘要 |
A zoom lens comprises, in order from an object side to an image side, a first lens unit of positive refractive power which is stationary during zooming, a second lens unit of negative refractive power which is axially movable during zooming, a third lens unit which is axially movable during zooming, and a fourth lens unit of positive refractive power which is stationary during zooming, wherein the first lens unit comprises a front lens sub-unit including at least one positive lens and having a negative refractive power as a whole, an intermediate lens sub-unit including at least one positive lens and a cemented lens and having a positive refractive power as a whole, and a rear lens sub-unit including a cemented lens and having a positive refractive power as a whole, and wherein the intermediate lens sub-unit is moved toward the image side to effect focusing from an infinitely distant object to an object at a minimum object distance./!
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