Zoom lens system for use in a microfilm projection apparatus

Details Zoom lens system for use in a microfilm projection apparatus Zoom lens system for use in a microfilm projection apparatus

1990-02-27

1991-11-05

Arnold, Bruce Y.

Optical: systems and elements

Lens

With variable magnification

30426, G02B 1517715/16

Patent

active

050626957

ABSTRACT:
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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