Abstract: A zoom lens with a function for reducing vibration, comprises in the order from an object side a first lens group having a negative refracting power and a second lens group movable in a direction traversing an optical axis and having a positive refracting power. When varying a focal length from a wide-angle end to a telephoto end, the first lens group moves non-linearly, and the second lens group moves toward the object side. The zoom lens also comprises a displacing device for reducing vibration by moving the second lens group in the direction traversing the optical axis. The zoom lens satisfies the following conditions:.DELTA.Y=(1-.beta..sub.2).multidot..DELTA.S.DELTA.Smax/f2<0.1where .DELTA.S is the magnitude of a vibration reduction moving quantity of the second lens group, .beta..sub.2 is the imaging magnification of the second lens group, .DELTA.Y is the magnitude of an image moving quantity corresponding thereto, f2 is the focal length of the second lens group, and .DELTA.

Abstract: A zoom lens system with vibration reduction function includes, in succession from the object side, a first lens unit having positive refractive power, a second lens unit movable along a direction across the optical axis thereof and having negative refractive power, a third lens unit, a fourth lens unit having positive refractive power, a fifth lens unit having negative refractive power, during the focal-length change from the wide angle end to the telephoto end, the spacing between the first lens unit and the second lens unit being increased, the spacing between the second lens unit and the third lens unit being varied, and the spacing between the fourth lens unit and the fifth lens unit being decreased, and a vibration reduction device for moving the second lens unit along the direction across the optical axis, the stabilization of an image on an image plane being accomplished by the movement of the second lens unit caused by the vibration reduction device.

Abstract: A rear conversion lens which has a negative refracting power and a function for magnifying, when mounted on an image side of an objective lens, an image formed by the objective lens, comprises, in the following order from an objective lens side, a first lens group having a positive refracting power and a second lens group having a negative refracting power. The lens groups are shifted as a whole in the direction perpendicular to the optical axis of the objective lens to stabilize the image magnified by the lens groups.

Abstract: A zoom lens includes, in the following order from the object side, a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, and a fourth lens group having a positive refracting power, and also includes a vibration reduction mechanism for attaining vibration reduction by shifting the third lens group or a partial lens group in the third lens group in a direction substantially perpendicular to an optical axis. When zooming is effected from the wide-angle end to the telephoto end, the interval between the first and second lens groups increases, the interval between the second and third lens groups decreases, and the interval between the third and fourth lens groups changes. The zoom lens satisfies the following condition:0.2<f3/(fW.fT).sup.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A zoom lens system with a vibration reducing function comprises, in the following order from the object side, a first lens group with a positive refractive power, a second lens group with a negative refractive power, a third lens group with a positive refractive power, and a fourth lens group with a positive refractive power. The fourth lens group has a front group with a positive refractive power and a rear group with a positive refractive power. When changing a focal length of the zoom lens system from a wide-angle end to a telephoto end, the distance between the first lens group and the second lens group is increased, and the distance between the second lens group and the third lens group and the distance between the third lens group and the fourth lens group are changed nonlinearly. The front group of the fourth lens group is shiftable in a direction traversing the optical axis of the zoom lens system.

Abstract: 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.

Abstract: In a zoom lens having a lens unit of negative refractive power most adjacent to the object side, distortion can be corrected better and an excellent imaging performance is maintained. In a zoom lens having a lens unit of negative refractive power most adjacent to the object side, a negative lens whose image side surface in contact with air is formed by a concave surface is provided in the lens unit of negative refractive power, and the shape of the concave surface of the negative lens is made into an aspherical surface which satisfies the condition that -5<.kappa.<0.75 with regard to a cone constant .kappa. and of which the curvature monotonically decreases away from the optical axis.

Abstract: Disclosed is a zoom lens of an internal focusing system, comprising: a positive focusing lens group positioned close to an object and incorporating a focusing function; and a zoom variable power optical system including a negative variable power lens group disposed towards an image of the focusing lens group and having such a variable power function as to be movable along an optical axis. The focusing lens group includes, sequentially from an object, a first lens element having a positive refractive power, a second lens element having a positive refractive power and movable along an optical axis and a third lens element having a negative refractive power. Only the second lens element is moved along the optical axis to change a synthetic focal distance of the focusing lens group, thus effecting focusing.

Abstract: The rear conversion lens of the present invention is compact and maintains an excellent imaging performance even when it is mounted on a telephoto objective lens the enlargement magnification of whose focal length is relatively high, e.g. about double and whose F-number is of the order of 2-2.8, and moreover does not intercept a light beam even in the fully open state of the aperture. The rear conversion lens of the present invention is an RCL adapted to be mounted on the image side of an objective lens and having negative refractive power for enlarging the combined focal length of itself and the objective lens, and has, in succession from the objective lens side, a first lens unit of positive or negative refractive power, a second lens unit of negative refractive power and a third lens unit of positive refractive power, the first lens unit having a positive lens most adjacent to the object side, and when the air gap between the first lens unit and the second lens unit is D.sub.