Abstract: A zoom lens in which a lens group located in the vicinity of an aperture stop includes two subgroups and one of the subgroups is shifted so that an image is shifted. An increase in the size of lens groups including a shift lens group can be prevented. In addition, the sensitivity with respect to the axis tilt can be reduced while maintaining a sufficient distance between the two subgroups without increasing the size of the lens groups.

Abstract: A zoom lens includes, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. When a lens positional state changes from a maximum wide angle state to a maximum telephoto state, the second lens group moves on an optical axis toward an object, and the first and the third lens groups also move in an optical axis direction such that a gap between the first lens group and the second lens group decreases, while gap between the second lens group and the third lens group is increased. When a change in subject position occurs, close-range focusing is performed by movement of the third lens group, and image shift is provided by shifting the second lens group in directions approximately perpendicular to the optical axis.

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: An electrode for an extra-high pressure discharge lamp, comprises large diameter portion which is symmetrical with respect to an axis of the electrode, a small diameter portion connected to the large diameter portion, wherein the large diameter portion is connected to the small diameter portion through an outer surface portion of the electrode, wherein a stripe lines like pattern portion, extending along an electrode axis direction, is formed on a portion to be brought in contact with glass of a lamp, and wherein unevenness is formed over an entire circumference of the electrode in a cross sectional view of the electrode taken along a direction perpendicular to the electrode axis direction.

Abstract: A zoom lens system includes, in order 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, a fourth lens unit having positive refractive power, and a fifth lens unit. When the lens positions change from the wide-angle end to the telephoto end, at least the first to fourth lens units are movable in an optical axis direction. The fifth lens unit includes a negative subunit having negative refractive power and a positive subunit having positive refractive power and being disposed on the image side of the negative subunit with a predetermined air gap the negative subunit and the positive subunit, and is capable of shifting the image by shifting the positive subunit in a direction substantially orthogonal to the optical axis.

Abstract: The object of the present invention is to provide a zoom lens in which a lens group located in the vicinity of an aperture stop includes two subgroups and one of the subgroups is shifted so that an image is shifted. Thus, an increase in the size of lens groups including a shift lens group can be prevented. In addition, the sensitivity with respect to the axis tilt can be reduced while maintaining a sufficient distance between the two subgroups without increasing the size of the lens groups. Accordingly, a sufficient performance can be provided. A zoom lens 3 includes at least three lens groups, that is, a negative lens group G2 having a negative refractive power, a shift lens group G3, and a positive lens group G4 having a positive refractive power arranged in this order from an object side.

Abstract: To provide a zoom lens capable of achieving stable optical quality by inhibiting an effect of assemble errors during manufacturing. A zoom lens includes a positive first lens group G1, a negative second lens group G2, a positive third lens group G3, and a positive fourth lens group G4, which are arranged from an object side in that order, and during variation in lens position from a wide angle end state to a telescopic end state, G1 and G3 are fixed, G2 is moved toward an image side, G4 moves so as to compensate fluctuations in image-surface position due to the shift of G2, and an aperture diaphragm S is fixed adjacent to the object side of G3, etc.

Abstract: A zoom lens and an imaging apparatus are disclosed. The zoom lens includes, in order from an object side to an image-plane side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power. During a change of a lens zoom position from a maximum wide angle state to a maximum telephoto state, at least the second lens group moves toward an image side, the third lens group moves toward an object side, and the fourth lens group is fixed in an optical-axis direction. An aperture stop is disposed near the object side of the third lens group. The first to fifth lens groups satisfy predetermined conditions.

Abstract: A zoom lens includes first to third lens groups having negative, positive, and positive refractive powers, respectively. When a lens position state changes from a wide-angle to a telephoto, all lens groups are moved in an optical axis direction so that a distance between the first and second lens groups decreases and a distance between the second and third lens groups increases. A close-distance focusing is accomplished by moving the third lens group. The first lens group is composed of negative and positive lens components. The second lens group is composed of a positive lens component, and a cemented lens composed of a positive lens of biconvex shape, and a negative lens of biconcave shape. The third lens group is composed of a positive lens component in which at least one of object-side and image-side lens surfaces is aspheric. The zoom lens is satisfied a predetermined condition.

Abstract: Provided are a zoom lens and an imaging apparatus using the zoom lens, the zoom lens being suited for achieving compactness without increasing the number of lenses and being capable of implementing motion blur compensation. The zoom lens includes lenses arranged in order from an object side into a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a fifth lens group having positive refractive power.

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: A zoom lens includes, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. When a lens positional state changes from a maximum wide angle state to a maximum telephoto state, the second lens group moves on an optical axis toward an object, and the first and the third lens groups also move in an optical axis direction such that a gap between the first lens group and the second lens group decreases, while gap between the second lens group and the third lens group is increased. When a change in subject position occurs, close-range focusing is performed by movement of the third lens group, and image shift is provided by shifting the second lens group in directions approximately perpendicular to the optical axis.

Abstract: A variable focal length lens system includes first to fourth lens groups having positive, negative, positive, and positive powers, respectively, and a fifth lens group arranged in this order from an object side. When a lens zoom position is changed from a wide-angle to a telephoto, the first to fourth groups are movable and the second group is moved towards the image side and the third group is moved towards the object side so that a distance between the first and second groups increases and a distance between the second and third groups decreases, and the fourth group is moved along an optical axis direction so as to compensate for the positional change in the image plane. The fifth group includes a negative subgroup having negative power and a positive subgroup disposed on the image side of the negative subgroup and having positive power, and a predetermined condition is satisfied.

Abstract: There are provided four lens groups including 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 positive refractive power, sequentially arranged from an object side. When a positional state of lenses is varied from a wide-angle-end state to a telephoto-end state, the second lens group is moved to an image side, the fourth lens group is moved for compensating a variation in a position of an image plane caused by the movement of the second lens group, and the first lens group and the third lens group are fixed along the optical axis. An aperture stop S is disposed at the object side of the third lens group.

Abstract: A zoom lens includes: a front group including a plurality of movable lens groups; and a rear group that is provided on an image side of the front group and that includes a negative lens and a positive lens. The positive lens has a flat lens surface on its image side, and is tiltable about a spherical center of its object side lens surface that is convex on the object side. When a lens system is inclined, the positive lens is tilted in relation to the optical axis of the lens system based on: a focal length of the overall lens system; an angle of the optical axis of the lens system after being inclined in relation to the optical axis before being inclined; a distance between the image side lens surface of the positive lens and the image plane; and a refractive index of the positive lens.

Abstract: A variable focal length lens system includes: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power. As the lens position state changes from a wide-angle end state to a telephoto end state, at least each of the lens groups is mobile, the second lens group moves towards the image side and the third lens group moves towards the object side such that the gap between the first and the second lens group increases, and the gap between the second and the third lens group decreases, while the fourth lens group moves in the direction of the optical axis so as to compensate for changes in the position of the image plane which accompany movements of each of the lens group.

Abstract: A variable focal length lens system includes: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power. As the lens position state changes from a wide-angle end state to a telephoto end state, at least each of the lens groups is mobile, the second lens group moves towards the image side and the third lens group moves towards the object side such that the gap between the first and the second lens group increases, and the gap between the second and the third lens group decreases, while the fourth lens group moves in the direction of the optical axis so as to compensate for changes in the position of the image plane which accompany movements of each of the lens group.

Abstract: A variable focal length lens system includes first to fourth lens groups having positive, negative, positive, and positive powers, respectively, and a fifth lens group arranged in this order from an object side. When a lens zoom position is changed from a wide-angle to a telephoto, the first to fourth groups are movable and the second group is moved towards the image side and the third group is moved towards the object side so that a distance between the first and second groups increases and a distance between the second and third groups decreases, and the fourth group is moved along an optical axis direction so as to compensate for the positional change in the image plane. The fifth group includes a negative subgroup having negative power and a positive subgroup disposed on the image side of the negative subgroup and having positive power, and a predetermined condition is satisfied.

Abstract: A zoom lens system includes, in order 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, a fourth lens unit having positive refractive power, and a fifth lens unit. When the lens positions change from the wide-angle end to the telephoto end, at least the first to fourth lens units are movable in an optical axis direction. The fifth lens unit includes a negative subunit having negative refractive power and a positive subunit having positive refractive power and being disposed on the image side of the negative subunit with a predetermined air gap the negative subunit and the positive subunit, and is capable of shifting the image by shifting the positive subunit in a direction substantially orthogonal to the optical axis.

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.