| 摘要 |
PROBLEM TO BE SOLVED: To realize a compact zoom converter lens while obtaining a desired variable power ratio. SOLUTION: The converter lens C attached to the front of a master lens M and capable of converting the focal distance of the master lens M has a 1st lens group L1 having positive refractive power, a 2nd lens group L2 having negative refractive power and a 3rd lens group L3 having positive refractive power in order from the front. In the case of varying power from the lowest afocal power to the highest afocal power, the 1st lens group L1 monotonously moves forward and the 2nd lens group L2 monotonously moves backward. The moving amounts of the 1st lens group L1 and the 2nd lens group L2 in the case of varying the power are appropriately set. COPYRIGHT: (C)2006,JPO&NCIPI
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