| 摘要 |
A small, lightweight zoom lens has high imaging performance with a large aperture and a large zoom ratio. The zoom lens includes a first lens unit having positive power, a second lens unit having negative power, and a third lens unit having positive and negative power components. During zooming, the second lens unit moves along the optical axis and the first lens unit is fixed. At least one of the lens surfaces of the first or second lens units is aspheric. The first lens unit has at least one positive lens component with refractive index Nd+ and Abbe number upsilon d+ that satisfies the following condition: Nd+<1.437 95< upsilon d+.
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