| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens having a short total retracted length and being capable of achieving satisfactory optical performance by satisfactory correction of chromatic aberration. SOLUTION: The zoom lens includes, in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a subsequent lens-unit set. Distances between the lens groups change during zooming. The first lens group includes a negative lens element, an optical element, and a positive lens element. Various parameters are set appropriately, including the Abbe numberνn and the partial dispersion ratioθgF of a material composing the optical element, the focal length f<SB>1n</SB>of the negative lens element and the Abbe numberν<SB>1n</SB>of a material composing the negative lens element, the focal length f1 of the first lens group, and respective lateral magnificationsβ<SB>3iw</SB>andβ<SB>3it</SB>of the subsequent lens-group set at a wide-angle end and at a telephoto end. COPYRIGHT: (C)2009,JPO&INPIT
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