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US 5,856,885 AGranted
Zoom lens
AssigneeFuji Photo Optical Co., Ltd.
InventorChikara Yamamoto
Life of this patent
Estimating the term…
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AssigneeFuji Photo Optical Co., Ltd.
InventorChikara Yamamoto
Estimating the term…
A zoom lens comprises, in order from the object end to the image end, a positive power first lens group, a negative power second lens group, a negative power third lens group, a positive power fourth lens group and a positive power fifth lens group. The second lens group is axially movable to vary the focal length of the zoom lens, and the fifth lens group is axially movable to correct a change in position of an image formed by the zoom lens caused during zooming and a change in position of an image formed by the zoom lens due to a change in object distance. The zoom lens satisfies at least the following condition: 0.8<F.sub.4 /(F*Z1.sup./2)<4.0 where F is the focal length of the overall zoom lens at the wide angle end position, F.sub.4 is the focal length of the fourth lens group of the zoom lens and Z is the zoom ratio of the zoom lens.
A zoom lens comprising, in order from the object end to the image end, a positive power first lens group, a negative power second lens group, a negative power third lens group, a positive power fourth lens group and a positive power fifth lens group, said second and fourth lens groups being axially movable in predetermined relation relative to each other and relative to the first, third and fifth lens groups which are stationary to focus and vary the focal length of the zoom lens, the zoom lens satisfying the following condition:
Dependencies are inferred from the claim text.