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Zoom lens system

Image Number 3 for United States Patent #5357374.

A zoom lens system consisting of three groups, wherein intervals between the groups are varied to thereby change a focal length. In this zoom lens system, the number of lenses constituting the groups is one, respectively. That is, a first group is constituted by a convex meniscus lens 11, a second group is constituted by a negative meniscus lens 12 directing a strong positive surface thereof toward an object and a third group is constituted by a negative meniscus lens 13 directing a strong convex surface thereof toward the object, whereby the number of the constituting lenses can be minimized to be three, and, because of the zoom lens system consisting of the three groups, the movement of the lens is scattered, so that the movement value of the lens for obtaining a desirable zooming ratio can be decreased.

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