| 摘要 |
A zoom lens which has good optical performance with the number of lenses used reduced as a result of forming a diffraction optical surface is disclosed. More specifically, there is disclosed a zoom lens that includes, in order of lens units from an object side to an image side, a first lens unit consisting of a positive lens element and having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a positive optical power. When zooming is performed from a wide angle end to a telephoto end, the first lens unit and the third lens unit are moved so that, at the telephoto end, they are positioned closer to the object side than to the wide angle end, and the second lens unit is moved so that, at the telephoto end, it is positioned closer to the image side than to the wide angle end. The zoom lens further includes at least one diffraction optical surface.
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