| 摘要 |
PROBLEM TO BE SOLVED: To provide a rear conversion lens capable of adequately correcting various aberrations and being applied in a master lens that has a large diameter. SOLUTION: The rear conversion lens comprises: a front group including a first lens group LG1 having a cemented lens with a positive refracting power, in which a negative meniscus lens, the convex face of which is on the object side and a positive lens, both faces of which are convex are cemented; and a rear group composed of a second lens group LG2 having a negative lens, both faces of which are concave, a third lens group LG3 having a positive lens, both faces of which are convex, and a fourth lens group LG4 having a negative lens, both faces of which are concave. The rear conversion lens RCL satisfies conditional expression (1) of the focal distance of the third lens group LG3, conditional expression (2) of a ratio between the focal distances of the second lens group LG2 and fourth lens group LG4, or conditional expression (3) defining the power of the cemented face of the first lens group LG1. COPYRIGHT: (C)2007,JPO&INPIT
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