| 摘要 |
PROBLEM TO BE SOLVED: To provide a telephoto lens which is improved in correcting chromatic aberration while suppressing increase in the number of pieces of anomalous dispersion glass to be used. SOLUTION: The telephoto lens is constituted of three groups as a whole, the 1st lens group 10 includes a 1st meniscus positive lens G11 having a convex surface on an object side, a negative lens G12 arranged at an image side of the 1st positive lens G11, and having a concave surface on the image side, and a 2nd positive lens G13 arranged at the image side of the negative lens G12, and having a convex surface on the object side. An inequality (1): 35<ν11<50, an inequality (2):ν12<45, an inequality (3): 75<ν13, and an inequality (4):ν12<ν11 are satisfied. In the inequalities,ν11 denotes Abbe's number of the 1st positive lens G11,ν12 denotes Abbe's number of the negative lens G12 andν13 denotes Abbe's number of the 2nd positive lens G13. COPYRIGHT: (C)2006,JPO&NCIPI
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