| 摘要 |
PROBLEM TO BE SOLVED: To make a lens driving mechanism simple by disposing a diaphragm at the most image surface side of a 1st lens group and integrally moving the 1st lens group and a 3rd lens group at a variable power time as for a zoom lens constituted of three positive, positive and negative groups. SOLUTION: This three-group zoom lens is constituted so that the positive, positive and negative lens groups I, II and III in order from an object side and a variable power action is executed by changing space between the respective lens groups. Besides, the diaphragm 2 is disposed at the most image surface side of the group I. Then, the groups I and III are integrally moved at the variable power time. The respective lens groups are moved so that the space between the groups I and II is increased and the space between the groups II and III is reduced toward a telephoto end from a wide angle end.
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