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Zoom lens system for use in a microfilm projection apparatus
Zoom lens system for use in a microfilm projection apparatus
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机译:用于微缩胶片投影设备的变焦镜头系统
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摘要
A zoom lens system comprising, in order from an enlargement side, a first lens unit of a negative power, a second lens unit of a positive power and a third lens unit of a negative power. The first lens unit is fixed during a zooming operation from a longest focal length condition to a shortest focal length condition. The second and third lens units are movable from the enlargement side to a reduction side during the zooming operation, with a distance therebetween changing from a decrease to an increase.
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