| 摘要 |
PROBLEM TO BE SOLVED: To provide a teleconverter lens which can reduce the size and weight of the whole optical system while maintaining excellent performance, and by which the manufacturing cost of the system is reduced by improving the productivity of an optical member in use. SOLUTION: The teleconverter lens which has a 1st lens group FL with positive refracting power and a 2nd lens group RL with negative refracting power from an object side to an image side and increases the focal length of a main lens ML arranged on the image side of the 2nd lens group RL is equipped with a lens element L12 having a diffracting optical surface Gf in at least one of the 1st lens group FL and 2nd lens group RL. Then this lens element L12 includes a glass member which has a≥75 Abbe number and a≤550°glass transition point. COPYRIGHT: (C)2004,JPO
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