| 摘要 |
PROBLEM TO BE SOLVED: To perform image angle broadening while reducing an effective aperture of a front lens group in an imaging lens by sequentially arranging a plurality of negative lenses and a positive meniscus lens directed at a convex surface to one focusing surface side from an object side at a most object side. SOLUTION: A negative first lens group G1, a diaphragm 3 and a positive second lens group G2 are arranged. The group G1 has a negative G1a in which a plurality of negative lenses and one positive meniscus lens sequentially arranged in this order from the object side, a negative G1b in which a single negative lens and positive, negative cemented lenses and a G1c having negative and positive doublets. When a focus is moved from an infinity object point to a close object point, the single negative lens in the G1b is moved along the optical axis X to the object side. The positive lens made of an anomalous dispersion material is arranged in the G2, and the negative lens made of the anomalous dispersion material is arranged in the G1, and the chromatic aberration is well corrected without increasing an amount of change of a back focus in association with a temperature change. COPYRIGHT: (C)2003,JPO
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