Abstract: A zoom lens includes, in order from an object side in an optical axis a first lens group having a positive refractive power, a second lens group having a negative refractive power; a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and an aperture stop arranged between the third lens group and the fourth lens group, an interval between the first lens group and the second lens group being increased, an interval between the second lens group and the third lens group being varied, an interval between the third lens group and the fourth lens group being decreased, and an interval between the fourth lens group and the fifth lens group being decreased when changing a magnification from a wide-angle end to a telephoto end.

Abstract: A zoom lens includes, in order from an object side to an image side along an optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power.

Abstract: A zoom lens includes, in order from an object side along an optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, wherein with a change in a magnification from a wide-angle end to a telephoto end, an interval between the first lens group and the second lens group is increased, the interval between the second lens group and the third lens group is changed, the interval between the third lens group and the fourth lens group is decreased, the interval between the fourth lens group and the fifth lens group is decreased, and focusing is performed by the third lens group.

Abstract: A zoom lens includes, in order from an object side in an optical axis a first lens group having a positive refractive power, a second lens group having a negative refractive power; a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and an aperture stop arranged between the third lens group and the fourth lens group, an interval between the first lens group and the second lens group being increased, an interval between the second lens group and the third lens group being varied, an interval between the third lens group and the fourth lens group being decreased, and an interval between the fourth lens group and the fifth lens group being decreased when changing a magnification from a wide-angle end to a telephoto end.

Abstract: A zoom lens includes, in order from an object side in an optical axis a first lens group having a positive refractive power, a second lens group having a negative refractive power; a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and an aperture stop arranged between the third lens group and the fourth lens group, an interval between the first lens group and the second lens group being increased, an interval between the second lens group and the third lens group being varied, an interval between the third lens group and the fourth lens group being decreased, and an interval between the fourth lens group and the fifth lens group being decreased when changing a magnification from a wide-angle end to a telephoto end.

Abstract: A zoom lens includes first to fifth lens groups having positive, negative, negative, positive, and positive refractive powers, respectively, arranged along an optical axis in order from an object side, and an aperture stop disposed between the third and fourth lens groups. When zooming from wide angle end to telephoto end, the zoom lens is moved so that an interval between the first and second lens groups increases, an interval between the second and third lens groups varies, an interval between the third and fourth lens groups decreases, and the third lens group focuses. The second lens group is arranged to have a focal length to satisfy the following condition: 0.95<|f2/?(fw*ft)|<4.0 where f2 is a focal length of the second lens group, fw and ft are focal lengths of the entire zoom lens at wide angle end and at telephoto end, respectively.

Abstract: A zoom lens includes first to fifth lens groups having positive, negative, negative, positive, and positive refractive power, respectively. The third lens group includes a single negative meniscus lens with a concave surface on an object side, to move along the optical axis for focusing. When zooming from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups increases, an interval between the third and fourth lens groups decreases, and an interval between the fourth and fifth lens groups decreases. The fourth and fifth lens groups are set to have a combined lateral magnification ?45T to satisfy the following condition, when an object distance is infinite at a telephoto end: ?0.041<?45T/Ft<?0.025 where Ft is a focal length of the entire zoom lens at the telephoto end.

Abstract: A zoom lens includes, in order from an object side along an optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, wherein with a change in a magnification from a wide-angle end to a telephoto end, an interval between the first lens group and the second lens group is increased, the interval between the second lens group and the third lens group is changed, the interval between the third lens group and the fourth lens group is decreased, the interval between the fourth lens group and the fifth lens group is decreased, and focusing is performed by the third lens group.

Abstract: A zoom lens includes, in order from an object side to an image side along an optical axis, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power.

Abstract: A zoom lens includes first to fifth lens groups having positive, negative, negative, positive, and positive refractive power, respectively. The third lens group includes a single negative meniscus lens with a concave surface on an object side, to move along the optical axis for focusing. When zooming from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups increases, an interval between the third and fourth lens groups decreases, and an interval between the fourth and fifth lens groups decreases. The fourth and fifth lens groups are set to have a combined lateral magnification ?45T to satisfy the following condition, when an object distance is infinite at a telephoto end: ?0.041<?45T/Ft<?0.025 where Ft is a focal length of the entire zoom lens at the telephoto end.

Abstract: A zoom lens includes, in order from an object side in an optical axis a first lens group having a positive refractive power, a second lens group having a negative refractive power; a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and an aperture stop arranged between the third lens group and the fourth lens group, an interval between the first lens group and the second lens group being increased, an interval between the second lens group and the third lens group being varied, an interval between the third lens group and the fourth lens group being decreased, and an interval between the fourth lens group and the fifth lens group being decreased when changing a magnification from a wide-angle end to a telephoto end.

Abstract: A zoom lens includes first to fifth lens groups having positive, negative, negative, positive, and positive refractive powers, respectively, arranged along an optical axis in order from an object side, and an aperture stop disposed between the third and fourth lens groups. When zooming from wide angle end to telephoto end, the zoom lens is moved so that an interval between the first and second lens groups increases, an interval between the second and third lens groups varies, an interval between the third and fourth lens groups decreases, and the third lens group focuses. The second lens group is arranged to have a focal length to satisfy the following condition: 0.95<|f2/?(fw*ft)|<4.0 where f2 is a focal length of the second lens group, fw and ft are focal lengths of the entire zoom lens at wide angle end and at telephoto end, respectively.

Abstract: A holding mechanism for a long length optical element, which extends in a main scanning direction that is a movement direction of a deflected luminous flux by an optical deflector, and leads the deflected luminous flux to a scanned surface, includes; a holding member which is placed in a sub-scanning direction orthogonal to the main scanning direction and holds the long length optical element in at least two places. The holding member has, an adjusting section which deflects the long length optical element in the sub-scanning direction and controls a tilt of the long length optical element in a sub-scanning cross-section and/or occurrences of a tilt distribution in a longitudinal direction in the sub-scanning cross-section.

Abstract: A zoom lens includes 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, being disposed in order from an object side, and an aperture stop disposed at an object side of the third lens group. When changing the magnification from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups decreases, and an interval between the third and fourth lens groups changes.

Abstract: A zoom lens 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, which are disposed in order from an object side, and an aperture stop disposed at an object side of the third lens group. When changing the magnification from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups decreases, and an interval between the third and fourth lens groups increases. The first lens group includes a negative lens, a positive lens, and a positive lens, in order from the object side. Predetermined conditions of a refractive index of the negative lens E1 for a d line, an Abbe number for d line, and a relative partial dispersion are satisfied.

Abstract: A zoom lens includes 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, being disposed in order from an object side, and an aperture stop disposed at an object side of the third lens group. When changing the magnification from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups decreases, and an interval between the third and fourth lens groups changes.

Abstract: A zoom lens includes 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, being disposed in order from an object side, and an aperture stop disposed at an object side of the third lens group. When changing the magnification from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups decreases, and an interval between the third and fourth lens groups changes.

Abstract: A zoom lens unit, including in order from an object side to an image 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, an aperture stop being disposed on an object side of the third lens group, wherein the third lens group has at least two positive lenses and one negative lens, wherein all the positive lenses of the third lens group satisfy the following formula: (1) ?0.005865?d3p+0.93226<?gF3p<?0.005865?d3p+0.95226, where, ?d3p represents an Abbe number of each of the positive lenses of the third lens group, and ?gF3p represents a partial dispersion ratio of each of the positive lenses of the third lens group, defined by the formula: ?gF3p=(ng?nF)/(nF?nC).

Abstract: A zoom lens 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, which are disposed in order from an object side, and an aperture stop disposed at an object side of the third lens group. When changing the magnification from a wide angle end to a telephoto end, an interval between the first and second lens groups increases, an interval between the second and third lens groups decreases, and an interval between the third and fourth lens groups increases. The first lens group includes a negative lens, a positive lens, and a positive lens, in order from the object side. Predetermined conditions of a refractive index of the negative lens E1 for a d line, an Abbe number for d line, and a relative partial dispersion are satisfied.

Abstract: A zoom lens unit, including in order from an object side to an image 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, an aperture stop being disposed on an object side of the third lens group, wherein the third lens group has at least two positive lenses and one negative lens, wherein all the positive lenses of the third lens group satisfy the following formula: (1) ?0.005865?d3p+0.93226<?gF3p<?0.005865?d3p+0.95226, where, ?d3p represents an Abbe number of each of the positive lenses of the third lens group, and ?gF3p represents a partial dispersion ratio of each of the positive lenses of the third lens group, defined by the formula: ?gF3p=(ng?nF)/(nF?nC).