| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide converter lens whose photographic viewing angle is extended to≥80°, further to≥100°, where the occurrence of aberration is little in spite of compact constitution, and which is excellent in imaging performance and fit for practical use. SOLUTION: The converter lens is equipped with a first lens group FL having negative refractive power and a second lens group RL having positive refractive power in order from an object side so as to constitute an afocal optical system. A negative meniscus lens L101 turning its convex surface toward the object side is arranged at the position nearest to the object side of the first lens group FL, and a biconvex lens L102 (at least one lens L102) is arranged in the second lens group RL. Then, a diffraction optical surface Gf is provided in the first lens group FL (at least either of the first and the second lens groups FL and RL). COPYRIGHT: (C)2004,JPO&NCIPI
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