Abstract: A zoom lens including a varifocal lens unit having a plurality of movable lens groups, and a prism disposed on an image side of the varifocal lens unit. The prism has an incident plane on which a light flux from the varifocal lens unit enters, and an exit plane from which the light flux is emitted toward an image plane, and is configured such that the incident plane or the exit plane or both planes can be inclined with respect to an optical axis, whereby a field of view is shifted by a predetermined amount by inclining the plane.

Abstract: A zoom lens includes a varifocal lens unit including a plurality of movable lens groups, and a prism disposed on an image side of the varifocal lens unit. The prism has an incident plane into which a light flux from the varifocal lens unit enters, and an exit plane from which the light flux is emitted toward an image plane, the exit plane capable of being inclined with respect to an optical axis, the exit plane inclined in accordance with a following conditional expression “?=?f×?/[Bf(n?1)]”, where ?: an angle formed by a normal of the exit plane and the optical axis, f: a focus distance of a whole lens system, ?: a turning angle of a lens system, Bf: a distance from the exit plane of the prism to the image plane along the optical axis, and n: a refraction index of the prism.

Abstract: There is provided a zoom lens capable of achieving stable optical quality even at the time of manufacture. The zoom lens includes a first lens group having positive refraction, a second lens group having negative refraction, a third lens group having positive refraction, and a fourth lens group having positive refraction, each being arrayed in this order from an object side, wherein: when a magnification changes from a wide-angle end condition having the shortest focal length to a telescopic end condition having the longest focal length, the first lens group and the third lens group are fixed in predetermined positions relative to the optical axis direction; the second lens group moves to the image side; and the fourth lens group moves to compensate fluctuation of the position of the image plane which is generated following moving of the second lens group.

Abstract: A zoom lens is disclosed which is superior in reduction of the lens diameter and can suppress degradation in performance while a high zoom ratio is achieved. The zoom lens is formed as a zoom lens of a four-group configuration having positive, negative, positive and positive groups. The second and fourth lens groups move whereas the first and third lens groups are fixed. An aperture stop is disposed on the object side of the third lens group. The third lens group includes negative and positive sub groups with an air distance left therebetween. The positive sub group is shiftable perpendicularly to the optical axis to shift an image substantially perpendicularly. A conditional expression 1.4<|f3n|/f3<3 is satisfied where f3n is the focal distance of the negative sub group and f3 is the focal distance of the third lens group.

Abstract: A zoom lens system having high zoom ratio capable of shifting an image for vibration reduction correction. The system includes, in order from an object, a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, and a fourth lens group having positive power. Each of the first lens group through the fourth lens group moves such that when zooming from a wide-angle end state to a telephoto end state, a distance between the first and the second lens groups increases, a distance between the second and the third lens groups decreases, and a distance between the third and the fourth lens group decreases. The third lens group includes at least two sub-lens groups having positive refractive power. Image shifting carried out by moving either of the two sub-lens groups perpendicularly to the optical axis. Given conditions are satisfied.

Abstract: Disclosed are a zoom lens and an imaging device. The zoom lens has a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fifth lens group including a negative subgroup with negative refractive power and a positive subgroup and with positive refractive power. An aperture stop is disposed in the vicinity of the third lens group. The lens surface of the negative subgroup of the fifth lens group on the image side and nearest to the image is concave, and the lens surface of the positive subgroup of the fifth lens group on the object side and nearest to the object is convex. The positive subgroup shifts in a direction approximately perpendicular to the optical axis to shift an image. The zoom lens satisfies the condition defined by the inequality (1) below: 0.2<f5p/ft<0.

Abstract: A variable focal length lens system realizing compactness and high zoom ratio is provided. The lens system includes four lens groups that are, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. When the state of lens group positions varies from a wide-angle end state to a telephoto end state, at least the first lens group is moved to the object such that a distance between the first and the second lens groups increases, a distance between the second and the third lens groups decreases, and a distance between the third and the fourth lens groups varies. An aperture stop is arranged in the vicinity of the third lens group. Given conditional expressions are satisfied.

Abstract: Disclosed are a zoom lens and an imaging device. The zoom lens has a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fifth lens group including a negative subgroup with negative refractive power and a positive subgroup and with positive refractive power. An aperture stop is disposed in the vicinity of the third lens group. The lens surface of the negative subgroup of the fifth lens group on the image side and nearest to the image is concave, and the lens surface of the positive subgroup of the fifth lens group on the object side and nearest to the object is convex. The positive subgroup shifts in a direction approximately perpendicular to the optical axis to shift an image. The zoom lens satisfies the condition defined by the inequality (1) below. 0.2<f5p/ft<0.

Abstract: There is provided a zoom lens capable of achieving stable optical quality even at the time of manufacture. The zoom lens includes a first lens group having positive refraction, a second lens group having negative refraction, a third lens group having positive refraction, and a fourth lens group having positive refraction, each being arrayed in this order from an object side, wherein: when a magnification changes from a wide-angle end condition having the shortest focal length to a telescopic end condition having the longest focal length, the first lens group and the third lens group are fixed in predetermined positions relative to the optical axis direction; the second lens group moves to the image side; and the fourth lens group moves to compensate fluctuation of the position of the image plane which is generated following moving of the second lens group.

Abstract: A zoom lens system having high zoom ratio capable of shifting an image for vibration reduction correction. The system includes, in order from an object, a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, and a fourth lens group having positive power. Each of the first lens group through the fourth lens group moves such that when zooming from a wide-angle end state to a telephoto end state, a distance between the first and the second lens groups increases, a distance between the second and the third lens groups decreases, and a distance between the third and the fourth lens group decreases. The third lens group includes at least two sub-lens groups having positive refractive power. Image shifting carried out by moving either of the two sub-lens groups perpendicularly to the optical axis. Given conditions are satisfied.

Abstract: A variable focal length lens system realizing compactness and high zoom ratio is provided. The lens system includes four lens groups that are, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. When the state of lens group positions varies from a wide-angle end state to a telephoto end state, at least the first lens group is moved to the object such that a distance between the first and the second lens groups increases, a distance between the second and the third lens groups decreases, and a distance between the third and the fourth lens groups varies. An aperture stop is arranged in the vicinity of the third lens group. Given conditional expressions are satisfied.

Abstract: A zoom lens system includes, in order from an object, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3. having positive refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a separation between the first lens group G1 and the second lens group G2 increases, a separation between the second lens group G2 and the third lens group G3 decreases, a separation between the third lens group G3 and the fourth lens group G4 varies, a separation between the fourth lens group G4 and the fifth lens group G5 increases, and the third lens group G3 and the fourth lens group G4 moving to the object side. Predetermined conditional expressions are satisfied.

Abstract: A zoom lens system includes, in order from an object, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a separation between the first lens group G1 and the second lens group G2 increases, a separation between the second lens group G2 and the third lens group G3 decreases, a separation between the third lens group G3 and the fourth lens group G4 varies, a separation between the fourth lens group G4 and the fifth lens group G5 increases, and the third lens group G3 and the fourth lens group G4 moving to the object side. Predetermined conditional expressions are satisfied.

Abstract: A variable focal length lens system comprises, from the object side, a positive first lens group, a positive second lens group and a negative third lens group. The lens groups are moved toward the object side such that, when changing from wide angle to telephoto, distance between the first lens group and the second lens group is increased and distance between the second lens group and the third lens group is decreased. An aperture stop disposed in the vicinity of the second lens group moves together with the second lens group; the third lens group is composed of a positive lens with the convex surface facing the image side and a negative lens disposed away from the positive lens toward the image side and having the concave surface facing the object side; and the positive lens is a double aspherical lens and satisfies predetermined conditions.

Abstract: A zoom lens system includes, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. When the lens system is changed from a wide-angle end to a telephoto end, each lens group is moved to the object side such that the separation between the first lens group and the second lens group increases, the separation between the second lens group and the third lens group decreases, and the separation between the third lens group and the fourth lens group decreases. The fourth lens group is composed of four lens elements arranged, in order from the object, a first positive lens element, a first negative lens element, a second positive lens element, and a second negative lens element.

Abstract: A variable focal length lens system comprising a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power and a third lens group G3 having a negative refractive power from the side of an object in this order; the respective lens groups are moved toward the object side in such a manner that, when the lens positional state is changed from a wide angle end state to a telephoto end state, a distance between the first lens group G1 and the second lens group G2 is increased and a distance between the second lens group G2 and the third lens group G3 is decreased; an aperture stop S is disposed in the vicinity of the second lens group G2; the aperture stop is moved together with the second lens group G2 in response to a change in the lens positional state so that the third lens group G3 is composed of a positive lens with the convex surface facing the side of an image and a negative lens which is disposed away from the positive lens with an air distance therebe

Abstract: A variable focal length lens system with an angle of view of more than 80 in the wide-angle end state capable to focusing to a near distant object is provided. According to one aspect, a variable focal length lens system includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a negative refractive power. When the state of lens positions is changed from a wide-angle end state to a telephoto end state, all the lens groups are moved to the object side such that the interval between the first lens group G1 and the second lens group G2 increases, the interval between the second lens group G2 and the third lens group G3 decreases, and the interval between the third lens group G3 and the fourth lens group G4 decreases.

Abstract: The object of the present invention is to provide a zoom lens system with a zoom ratio of seven or more suitable for compactness capable of obtaining stable optical performance in spite of reducing the number of lenses. According to one aspect of the present invention, a zoom lens system includes, in order from an object, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having positive refractive power. When the state of lens group positions of the zoom lens system is changed from a wide-angle end state to a telephoto end state, each lens group is moved to the object side such that the separation between the first lens group G1 and the second lens group G2 increases, the separation between the second lens group G2 and the third lens group G3 decreases, and the separation between the third lens group G3 and the fourth lens group G4 decreases.

Abstract: A variable focal length optical system of reducing size and increased zoom ratio is provided. According to one aspect. at least three lens groups, in order from an object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a negative refractive power. When a state of lens group positions is changed from a wide-angle end state to a telephoto end state, each lens group moves to the object side such that an air gap between the first lens group G1 and the second lens group G2 increases, and an air gap between the second lens group G2 and the third lens group G3 decreases. An aperture diaphragm is arranged between the first lens group G1 and the third lens group G3. The second lens group G2 is arranged in the vicinity of the aperture diaphragm and has a positive lens having double aspherical surfaces. Particular conditions are satisfied.

Abstract: A variable focal length lens system includes at least three lens groups, in order from an object side, a first lens group G1, a second lens group G2, and a third lens group G3. When the lens group positions are changed from a wide-angle end state to a telephoto end state, each lens group moves from a state focused at infinity to a state focused at near object, in order from a state focused at infinity in the wide-angle end state to a state focused at near object in the telephoto end state. G2 has an aperture diaphragm S, and lens elements are arranged to both object and image side of the aperture diaphragm S.