| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in the performance of a zoom lens caused by misalignment of the axis by manufacture error. SOLUTION: The zoom lens includes, in the order from the object side to the image side, a first lens group L1 having positive refractive power, a second lens group L2 having negative refractive power, a third lens group L3 having positive refractive power, a fourth lens group L4 having positive refractive power, with each spacing between the lens groups variable on zooming. The third lens group L3 consists of, in the order from the object side to the image side, a third-a lens group L3a having positive refractive power and having a positive lens with a convex face in the object side, an aperture stop SP, a third-b lens group L3b having negative refractive power and having a negative lens, a third-c lens group L3c having positive refractive power and a positive lens. The spacing between the third-a lens group L3a and the third-b lens group L3b, the spacing between the third-b lens group L3b and the third-c lens group L3c, the thickness of the third-c lens group L3c in the optical axis direction, and other factors are appropriately determined. COPYRIGHT: (C)2005,JPO&NCIPI
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