| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens having a wide viewing angle, which has high optical performance over the whole zoom region. SOLUTION: The zoom lens has a first lens group having negative refractive power and a second lens group having positive refractive power in order from an object side to an image side and when zooming is performed from a wide angle end to a telephoto end, the first and second lens groups are moved. The first lens group has three negative lenses and at least one positive lens in order from the object side to the image side and at least one of the respective surfaces of these lenses has an aspherical surface shape. In the lens surface constituting the first lens group, the center of curvature is on an optical axis, a spherical surface including a point where the lens surface crosses the optical axis and a point on the lens surface determined from an effective diameter, on the surface thereof is defined as a reference spherical surface, and the radius of curvature r12 of the reference spherical surface on the image side of the negative lens on the most object side of the first lens group and the radius of curvature r21 of the reference spherical surface on the object side of the second negative lens counted from the object side are properly set. COPYRIGHT: (C)2009,JPO&INPIT
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