| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens capable of achieving a half angle of view over 38°at the wide-angle end, a magnification ratio 6.5 to 10 or more, and a resolving power corresponding to an imaging element of 5 to 8 million pixels, with a configuration of as few as 10 to 11 pieces of lenses. SOLUTION: The zoom lens includes a first lens group through a third lens group I to III of positive/negative/positive in order from the object side, or further includes a fourth lens group of positive IV. In the zoom lens, when changing magnification from a wide-angle end toward a telephoto end, the lens groups are moved so that a spacing between the first lens group and the second lens group increases and a spacing between the second lens group and the third lens group decreases. On an orthogonal two-dimensional coordinate plane taking a partial dispersion ratioθ<SB>g,F</SB>and an Abbe numberν<SB>d</SB>, when a straight line connecting a coordinate point (ν<SB>d</SB>=60.49,θ<SB>g,F</SB>=0.5432) of a standard glass type K7 and a coordinate point (ν<SB>d</SB>=36.26,θ<SB>g,F</SB>=0.5830) of a standard glass type F2 is defined as a standard line, and a deviation of the partial dispersion ratioΔ<SB>g,F</SB>of the glass type from the standard line on the two-dimensional coordinate plane is defined as an anomalous dispersivenessΔθ<SB>g,F</SB>of the glass type, a refractive index N<SB>d</SB>and the Abbe number v<SB>d</SB>and the anomalous dispersivenessΔθ<SB>g,F</SB>of at least one positive lens of the third lens group III satisfy the following condition (1) through the condition (3). Nd>1.58 (1),ν<SB>d</SB>>60.0 (2) and 0.05>Δθg, F>0.003 (3). COPYRIGHT: (C)2008,JPO&INPIT
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