Nikon Corporation

Masahiro Nakatsuji

Kenzaburo Suzuki

Kiyotaka Inadome

Toru Takayama

Susumu Sato

Hideo Kanno

Atsushi Shibayama

Haruo Sato

Kunihiro Fukino

Keiji Moriyama

A zoom lens includes at least two lens groups, i.e., a first lens group and a second lens group. The second lens group includes a first sub-group near to the first lens group and a second sub-group far from the first lens group, and the first lens group and the first sub-group in the second lens group together form a substantially afocal system in at least a portion of a zooming range. In the zoom lens, focusing is effected by the first sub-group in the second lens group being moved along the optical axis. Considering a case where this zoom lens is applied for auto focusing, it is preferable that the first lens group be disposed on that side in the lens group which is most adjacent to the object side.

Zoom lens

A high-magnification zoom lens having a lens system that is movable from a wide angle setting to a telephoto setting includes five lens groups. The lens system has a focal length of fW in the wide angle setting and a focal length of fT in the telephoto setting. The five lens groups are arranged in order from an object side along an optical axis that extends from a center of the lens system. A first lens group G1 has a positive refractive power and a focal length of f1, a second lens group G2 has a negative refractive power and a focal length of f2, a third lens group G3 has a negative refractive power and a focal length of f3, a fourth lens group G4 has a positive refractive power, and an image composing lens group GR has a positive refractive power. When the lens system changes from the wide angle setting to the telephoto setting, the first lens group G1 and the fourth lens group G4 move such that a distance between the first lens group G1 and the second lens group G2 increases, a distance between the third lens group G3 and the fourth lens group G4 decreases, and several conditions are satisfied.

High magnification zoom lens

A zoom lens having a four-unit lens construction with positive, negative, positive, and positive refractive powers. In an embodiment, the second lens unit is moved toward the image side during the magnification change from the wide angle end to the telephoto end, and the third lens unit is moved in a direction substantially orthogonal to the optical axis to effect image stabilization. The zoom lens satisfies the condition that .DELTA.Y=f.sub.4 /f.sub.3 .multidot..DELTA.S. In another embodiment, the first, third, and fourth lens units are moved toward the object side during the magnification change from the wide angle end to the telephoto end, and the second lens unit is moved in a direction substantially orthogonal to the optical axis to effect image stabilization. The zoom lens satisfies the condition that .DELTA.Y=(1-.beta..sub.2).multidot..beta..sub.34 .multidot..DELTA.S.

Zoom lens equipped with the image stabilizing function

A zoom lens of five group construction utilizing an inner focus system. The zoom lens includes a first lens group G1 having a positive refracting power, a second lens group G2 having a negative refracting power, a third lens group G3 having a negative refracting power, a fourth lens group G4 having a positive refracting power and a fifth lens group G5 having a negative refracting power, which are arranged in this order from an object side, and the distances among the respective lens groups are selectively varied to effect the desired zooming operation. During close-up photographing, the second lens group G2 is moved along an optical axis to effect the desired focusing.

Zoom lens utilizing inner focus system

A zoom lens system, with both zooming and focusing functions, has a plurality of lens groups including at least two focusing lens groups which move differently from each other either in zooming or in focusing, wherein when a certain movement trace for zooming is expressed with a variable of rotation angle of a rotating barrel for defining a displacement amount of a lens group along an optical axis, a movement trace of the first focusing lens group is formed by a combination of a first focus cam with a first compensating zoom cam, a movement trace of an n-th focusing lens group is formed by a combination of an n-th focus cam with an n-th compensating zoom cam, and a movement trace of each movable non-focusing lens group taking no part in focusing is formed by a combination of one of the first to n-th compensating zoom cams with a zoom cam for the non-focusing lens group.

Zoom lens system

A telephoto zoom lens, sequentially from an object, comprising: a first lens group having positive refracting power; a second lens group having negative refracting power; a third lens group having negative refracting power; a fourth lens group having positive refracting power; and a fifth lens group having negative refracting power. During variable power from a wide-angle end to a telephoto end, the lens groups move so that a space dimension between the first and second lens groups increases, a space dimension between the second and third lens groups changes linearly or nonlinearly, and a space dimension between the fourth and fifth lens groups decreases. The zoom lens satisfies various conditions.

Telephoto zoom lens for 35 mm photos

A zoom lens incorporating a vibration-proofing function comprises, sequentially from an object side, a first lens group G.sub.1 having a positive refracting power; a second lens group G.sub.2 having a negative refracting power; a third lens group G.sub.3 having a negative refracting power; a fourth lens group G.sub.4 having a positive refracting power; and a fifth lens group G.sub.5 having a negative refracting power. The lens groups move so that when varying a magnifying power from a wide-angle end to a telephoto end, a spacing between the first and second lens groups G.sub.1, G.sub.2 increases; a spacing between the second and third lens groups G.sub.2, G.sub.3 changes linearly or non-linearly; and a spacing between the fourth and fifth lens groups G.sub.4, G.sub.5 is reduced. The zoom lens comprises a shift means for moving one of the third and fourth lens groups G.sub.3, G.sub.4 perpendicularly across the optical axis.

Zoom lens incorporating vibration-proofing function

In an internal focus telephoto lens comprised, in succession from the object side, of a first lens unit of positive refractive power, a second lens unit of negative refractive power and a third lens unit of positive refractive power, the first lens unit of positive refractive power and the second lens unit of negative refractive power together forming a substantially afocal system, focusing being effected by the second lens unit, the first lens unit has a front group of positive refractive power and a rear group having weak positive refractive power relative to the front group, the first group being comprised, in succession from the object side, of a positive lens component, a positive lens component and a negative lens component, the second lens unit has, in succession from the object side, at least a negative lens component and a negative lens component, and the third lens unit has a positive lens component, and various predetermined conditions are satisfied.

Internal focus telephoto lens for an auto focus camera

A wide-angle zoom lens has a first lens group having a positive refracting power and a second lens group having a negative refracting power, which are moved relative to each other along the optical axis so as to attain zooming. The first lens group is constituted in turn from the object side by a front group having a negative refracting power and a rear group having a positive refracting power. The front group has at least one negative lens. The rear group has at least two positive lenses. The zoom lens is constituted to satisfy the following conditions:

Wide-angle zoom lens

In a zoom lens system having a plurality of lens units including a focusing lens unit movable during zooming and having the zooming and focusing functions, when a predetermined movement locus for zooming is expressed with the angle of rotation of a rotatable lens barrel for prescribing the amount of movement of the lens units in the direction of the optical axis thereof as a variable, the movement locus of the focusing lens unit is formed by the combination of a focus cam and a zoom compensation cam, and the movement locus of the movable non-focusing lens units which are not concerned in focusing is formed by the combination of the zoom compensation cam and a zoom cam corresponding to each non-focusing lens unit.

A great relative aperture telephoto zoom lens of four-unit construction has, in succession from the object side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, and a fourth lens unit having positive refractive power. The fourth lens unit has, in succession from the object side, a front group having positive refractive power and a rear group having positive refractive power. The front group has, in succession from the object side, two positive lens components and a negative lens component. The rear group has, in succession from the object side, a positive lens component and a negative lens component, and is designed to satisfy predetermined conditions.

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Kawasaki, Japan

Masahiro Nakatsuji