Zoom lens system
AssigneeOlympus Optical Co., Ltd.
InventorToshihiro Imai
Life of this patent
Estimating the term…
Abstract
A zoom lens system has a plurality of lens groups movable at the time of zooming and one of the lens groups comprises a plurality of lens components having a positive and a negative lens components. Focusing is done by both the variation of the relative position of respective lens components of the lens group and the movement of the lens group as a whole. This arrangement enables the zoom lens system to be made compact and the moving mechanism of the lens group simple.
Claims6
A zoom lens system comprising a plurality of lens groups disposed along an optical axis, one of which is located on the most object side of such axis and is movable along said optical axis at the time of zooming, another of said lens groups, arranged at another position on said axis and comprising a positive lens component and a negative lens component, whereby focusing is done by moving said another lens group along said optical axis at the same time changing the relative distance between said positive lens component and said negative lens component, and the moving amounts of said another lens group and said positive and negative lens components is constant for any value of focal length of the lens system as a whole, wherein one of said lens groups, except said another lens group for focusing, is movable along said optical axis so that focusing for objects positioned in a range is done, except the range for which focusing can be done by moving said another lens group.
Dependencies are inferred from the claim text.