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US 5,331,463 AGranted
Wide angle zoom lens system
AssigneeOlympus Optical Co., Ltd.
InventorTakanori Yamanashi
Life of this patent
Estimating the term…
Abstract
A wide angle zoom lens system comprising, in order from the object side, a first positive lens unit, a second positive lens unit and a third negative lens unit; and configured so as to perform variation of focal length by varying airspaces reserved between these lens units. The first lens unit consists of a negative front subunit and a rear positive subunit. The zoom lens system has a wide field angle and favorable optical performance.
Claims15
A wide angle zoom lens system comprising, in order from the object side:
- a first lens unit having positive refractive power, a second lens unit having positive refractive power, and a third lens unit having negative refractive power wherein focal length is varied by varying airspaces reserved between said lens units, and wherein said first lens unit consists of a front subunit and a rear subunit, and said first lens unit satisfies the following condition ( 1 ):
- .vertline..phi..sub.f /.phi..sub.1 .vertline.<6.0 (1)
- wherein the reference symbol .phi..sub.1 represent refractive power of said first lens unit and the reference symbol .phi..sub.f designates refractive power of said front subunit.
Dependencies are inferred from the claim text.