| 摘要 |
PROBLEM TO BE SOLVED: To make a system small in size and high variable power by moving a positive lens and a final lens and always satisfying a specified condition at the time of changing the position of a lens from the wide-angle end to the telescopic end. SOLUTION: At the time of changing the position of a lens from the wide-angle end to the telescopic end, an air gap between a first lens G1 and a second lens G2 is increased. An air gap between the second lens G2 and a third lens G3 is decreased and an air gap between the third lens G3 and a fourth lens G4 is increased,. The respective lens groups are moved to the object side so that an air gap between the fourth lens G4 and a fifth lens G5 is decreased and an air gap between the fifth lens G5 and a sixth lens G6 is increased. By representing the moving amount of the positive lens G1 byΔG1 and the moving amount of the final lens to a prescribed position of lens on the basis of the wideangle end byΔGe, at the time of changing of the lens position, the condition: 0.3<|ΔGe/ΔG1|<0.6 is always satisfied.
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