Abstract: A zoom lens system according to the present invention includes a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with positive refractive power, and a fourth lens group with negative refractive power which are arranged in turn from the object side toward the image side, and the zoom lens system is formed so that, in performing a zooming operation from the wide angle end position to the telephoto end position, the first lens group keeps still, the distance between the first and second lens groups becomes small, the distance between the second and third lens groups becomes wide, and the distance between the third and fourth lens groups becomes small.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group, and a positive fourth lens group. Upon zooming from the short to the long focal length extremities, the distance between the first and second lens groups decreases, the distance between the second and third lens groups increases, and the distance between the third and fourth lens groups decreases. The following conditions (1) and (2) are satisfied: ?2.50<f1/f2<?1.57??(1), and f3/f3B<?0.1??(2), wherein f1, f2 and f3 designate the focal lengths of the first, second and third lens groups, respectively, and f3B designates the focal length of a bonding surface in the cemented lens of the third lens group.

Abstract: A zoom lens includes sequentially from an object 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 positive refractive power, and a fifth lens group having a negative refractive power. The zoom lens satisfies given conditions to implement a compact, wide angle, large aperture ratio zoom lens having excellent optical performance and compatible with solid state image sensors capable of recording full high vision images.

Abstract: The invention is an optical lens assembly for capturing images and an image capture device therewith. The optical lens assembly for capturing images includes, along an optical axis, a total reflection prism, a first lens group having negative focal power, wherein the first lens group comprises a lens having negative focal power, a second lens group having positive focal power, wherein the second lens group comprises at least one lens having an aspherical optical surface, a third lens group having positive focal power, wherein the third lens group comprises at least one lens having positive focal power and at least one lens having negative focal power, and a fourth lens group having positive focal power, wherein the fourth lens group comprises at least one lens having an aspherical optical surface. Thereby, the aberration can be improved and a thin lens module for capturing images can be achieved.

Abstract: An inner focus lens, in order from an object side to an image side, comprising: a first lens unit having positive optical power; a second lens unit having negative optical power; and a third lens unit having positive optical power, wherein the second lens unit is moved along an optical axis so that focusing from an infinite-distance object side to a short-distance object side is achieved, the first lens unit includes a bi-convex air lens, and the following conditions: 0.65<|f2/f|<5.00 and 0.5<f23/f1<9.0 (f2: a focal length of the second lens unit, f and f23: a focal length of the entire system and a composite focal length of the second and third lens units in an infinity in-focus condition, f1: a focal length of the first lens unit) are satisfied; an interchangeable lens apparatus; and a camera system are provided.

Abstract: An image pickup apparatus includes: a zoom lens; an image pickup element having an image pickup surface which receives an image which has been formed by the zoom lens, and converts to an electric signal; a shading correction parameter storage section which stores a shading correction parameter which differs at a front-surface side and a rear-surface side with respect to a center of an image, which is for correcting asymmetric shading at the front-surface side and the rear-surface side of the zoom lens; and a shading correction section which carries out correction operation of an image which has been picked up by the image pickup element, based on the shading correction parameter of the shading correction parameter storage section. When an object having a uniform brightness is captured, at any state from the wide angle end to the telephoto end, the zoom lens satisfies conditional expression (A).

Abstract: A zoom lens includes a first lens group that has a lens having negative refractive power and a light path changing member; a second lens group that includes a lens having positive refractive power and a lens having negative refractive power, and has negative refractive power as a whole; a third lens group that includes a stop, a front group lens having positive refractive power, and a rear group lens having negative refractive power, and has positive refractive power as a whole; and a fourth lens group having positive or negative refractive power. Upon changing magnification from a wide-angle end to a telephoto end, the first lens group and the fourth lens group are fixed. The second lens group moves to the object side after the second lens group moves to an image side, and the third lens group linearly moves to the object side.

Abstract: A zoom lens includes: a first lens group having a positive power; a second lens group having a negative power; a third lens group having a positive power; and a fourth lens group having a negative power, in this order from an object side. All of the groups move along an optical axis such that the distance between the first group and the second group gradually becomes greater, the distance between the second group and the third group gradually becomes smaller, and the distance between the third group and the fourth group gradually becomes greater, when changing magnification from a wide angle to a telephoto end. The zoom lens satisfies the conditional formulae: ?2.0<fw/f2<?0.8; and ?1.0<fw/f4<?0.2, wherein fw is the focal length of the entire system at the wide angle end, f2 is the focal length of the second group, and f4 is the focal length of the fourth group.

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 negative refractive power provided in this order from an object side. All of the lens groups move along an optical axis such that the distance between the first lens group and the second group gradually becomes greater, the distance between the second lens group and the third lens group gradually becomes smaller, and the distance between the third lens group and the fourth lens group gradually becomes greater when changing magnification from a wide angle end to a telephoto end. The fourth lens group practically includes a lens having a positive refractive power, a lens having a negative refractive power, and a lens having a positive refractive power.

Abstract: A zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group. The first lens group includes a first lens that has positive refractive power, a second lens that has negative refractive power, and a prism. The second lens group includes a third lens that has positive refractive power and a fourth lens that has negative refractive power. The third lens group includes a stop, a fifth lens that has positive refractive power, and a sixth lens that has negative refractive power. The fourth lens group includes a seventh lens that has positive refractive power. Upon changing magnification from a wide-angle end to a telephoto end, the first and fourth lens groups are fixed, the second lens group first moves toward an image plane side and then moves toward an object side, and the third lens group linearly moves toward the object side.

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. When the zoom lens is zoomed from a wide-angle end state to a telephoto end state, the first lens group is moved toward the object side so that a distance between the first and second lens groups increases and the third lens group is moved toward the object side so that a distance between the second and third lens groups decreases. The second lens group includes three lenses: negative, positive, and negative lenses in order from the object side to the image side. The third lens group includes three lenses: positive, negative, and positive lenses in order from the object side to the image side.

Abstract: A variable magnification optical system for projection includes a first-lens-group having negative refractive power, and which is fixed when magnification of the system is changed, a second-lens-group having negative refractive power, and which is movable when magnification of the system is changed, a third-lens-group having positive refractive power, and which is movable when magnification of the system is changed, and a fourth-lens-group having positive refractive power, and which is fixed when magnification of the system is changed, which are arranged from the magnification side of the system in the order mentioned. The reduction side of the variable magnification optical system is telecentric, and formula 1.5<Bf/fw is satisfied, where Bf: back focus in air of entire system at wide angle end, and fw: focal length of entire system at wide angle end.

Abstract: There is provided a zoom lens including first and second lens groups independently movable in an optical axis direction in an optical system. Before and after switching between two modes different in minimum focusing distance, a lens group to rule focusing changes between the first and second lens groups or a relative position between the first and second lens groups changes.

Abstract: An image capturing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element with negative refractive power has an object-side surface being convex and an image-side surface being concave. The second lens element with positive refractive power has an object-side surface and an image-side surface being both convex. The third lens element with positive refractive power has an object-side surface being concave and an image-side surface being convex. The fourth lens element with positive refractive power has an object-side surface being convex, and an image-side surface being concave at a paraxial region and being convex at a peripheral region, wherein the surfaces of the fourth lens element are aspheric.

Abstract: A zoom lens includes, 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. All of the lens units are moved during zooming from a wide-angle end to a telephoto end. An aperture stop is arranged on the image side of the third lens unit. A distance T23 from a lens surface closest to the image side in the second lens unit to a lens surface closest to the object side in the third lens unit when the zoom lens is at the telephoto end, a focal length fT of the entire zoom lens at the telephoto end, and focal lengths f1, f2, and f3 of the first, second, and third lens units, respectively, are set based on predetermined mathematical conditions.

Abstract: A zoom lens system comprising: a first lens unit having positive optical power; a second lens unit having positive optical power; and at least one subsequent lens unit, wherein the zoom lens system has an image blur compensating lens unit which moves in a direction perpendicular to an optical axis, at least the first lens unit moves along the optical axis at the time of zooming from a wide-angle limit to a telephoto limit, the second lens unit or a third lens unit which is located closest to the object side in the at least one subsequent lens unit moves along the optical axis at the time of focusing from an infinity in-focus condition to a close-object in-focus condition, and the condition: 0.10<|m|/(fT?fW)<0.

Abstract: Disposing from an object side in the order of a positive first lens group which is fixed at the time of zooming, a negative second lens group which is moved at the time of zooming, an aperture stop, a positive third lens group which is fixed at the time of zooming, and a fourth lens group which is moved along the optical axis at the time of zooming to correct a change in image plane position arising from the zooming for focusing. When a refractive index of the third group first lens with respect to d-line, a focal length of the third group, and focal lengths of the overall lens system at a wide angle end and a telephoto end are taken as Nd31, f3, fw, and ft respectively, conditional expressions (1): 1.77<Nd31 and (2): 0.8<f3/(fw·ft)1/2<1.6 are simultaneously satisfied.

Abstract: A zoom lens includes, in order from an object side: a first lens unit having positive refractive power which does not move for varying magnification; a magnification-varying lens unit including at least two lens units which move for varying magnification; an aperture stop; and an imaging lens unit having positive refractive power which does not move for varying magnification, in which: the first lens unit includes, in order from the object side, a first sub-lens unit having positive refractive power, a second sub-lens unit having negative refractive power, and a third sub-lens unit having positive refractive power; the second sub-lens unit is driven to the object side so as to perform focus adjustment to an object at a short distance; and the following expression is satisfied: 0.07<f1/f11<0.35, where f1 represents a focal length of the first lens unit, and f11 represents a focal length of the first sub-lens unit.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of a negative refractive power, a second lens unit of a positive refractive power, and a third lens unit of a positive refractive power, an interval between the first lens unit and the second lens unit and an interval between the second lens unit and the third lens unit being configured to change in zooming from a wide angle end to a telephoto end. The first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens. The predetermined conditions are satisfied.

Abstract: The zoom lens includes first to fourth lens units respectively having negative, positive, negative and positive refractive powers and being moved during zooming. The first lens unit includes 1-1 and 1-2 negative lenses each having a meniscus shape with an object side convex surface. The conditions of ?4.0<f11/fw<?1.5,1.5<(R11b+R11a)/(R11b?R11a)<5.0 and 1.4<h12/D12<2.0 are satisfied where f11 represents a focal length of the 1-1 lens, fw represents a focal length of the zoom lens at a wide-angle end, R11a and R11b respectively represent curvature radii of the object side surface and an image side concave surface of the 1-1 lens, h12 represents half of an effective diameter of an image side aspheric surface of the 1-2 lens, and D12 represents a distance from an effective diameter position in the image side surface of the 1-2 lens to an apex of the image side aspheric surface thereof.

Abstract: Provided is a zoom lens, including in order from a magnification conjugate side to a reduction conjugate side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a third lens unit having a positive refractive power; a fourth lens unit having a negative refractive power; a fifth lens unit having a negative refractive power; and a sixth lens unit having a positive refractive power. The first and sixth lens units do not move for zooming, while the second to fifth lens units move to the magnification conjugate side during zooming from a wide-angle end to a telephoto end. Each of the second and third lens units is composed of a single positive lens. Movement amounts of the second, third and fourth lens units during zooming from the wide-angle end to the telephoto end satisfy appropriate relationships.

Abstract: An optical system for imaging an object on an image acquisition unit. The optical system, from the object, comprises a first lens unit, a second lens unit, a third lens unit and a fourth lens unit in the direction of the image acquisition unit. The first lens unit comprises at least one lens group with negative refractive power. The second lens unit comprises at least one lens group with positive refractive power and the third lens unit comprises at least one lens group with negative refractive power. The second lens unit and the third lens unit overall comprise at least three lens groups. From the first lens unit in the direction of an image acquisition unit, the first lens group, the second lens group and then the third lens group are arranged. The three lens groups have a movable design for adjusting the focal length of the optical system.

Abstract: A zoom lens includes: a first lens group having negative refractive power; a diaphragm; a second lens group having positive refractive power; a third lens group having negative refractive power; and a fourth lens group having positive refractive power, arranged in order from an object side. The first lens group is configured by at least one negative lens and one positive lens. The third lens group is configured by one negative lens. Then power is changed from a wide angle end state to a telephoto end state, the first, second, and third lens groups are moved in the direction of an optical axis, and the fourth lens group is fixed. When focusing, the third lens group is moved in the direction of the optical axis so as to satisfy the following Conditional Equations, ?2.8<f3/fw<?0.5??(1) 2.0<f4/fw<15.0??(2).

Abstract: A zoom lens includes a first lens unit (positive), a second lens unit (negative), a third lens unit (positive), and a rear lens group having one or more lens units. During zooming from the wide-angle end to the telephoto end, the distance between the first and second lens units increases, the distance between the second and third lens units decreases, and the distance between the third lens unit and the rear lens group changes. The first lens unit consists of a positive lens and a negative lens. The following conditional expressions are satisfied: 8.0<f1/fW<30.0 and 2.0<?2T/?2W<10.0, where f1 is a focal length of the first lens unit, fW is a focal length of the entire system at the wide-angle end, and ?2W and ?2T are respectively lateral magnifications of the second lens unit at the wide-angle end and the telephoto end.

Abstract: A zoom lens includes, in order from an object side to an image side, first to fourth lens units having negative, positive, negative, and positive refractive power, respectively. Each lens unit moves during zooming so that a distance between the first lens unit and the second lens unit at the telephoto end is shorter than at the wide-angle end and a distance between the second lens unit and the third lens unit and a distance between the third lens unit and the fourth lens unit at the telephoto end are larger than those at the wide-angle end. A focal length of the third and fourth lens units, a focal length of the entire zoom lens at the wide-angle end, a focal length of the entire zoom lens at the telephoto end, and a sum of axial thicknesses of the first to fourth lens units are appropriately set.

Abstract: a zoom lens includes, in order from object side: a positive first unit immovable for zooming; a negative second unit moving during zooming; a third unit moving during zooming; a stop; and a positive fourth unit immovable for zooming. The first unit includes, in order from object side, a fixed negative front first unit, a positive middle first unit moving for focusing, and a fixed positive rear first lens unit. Each of the front first and the second units includes at least one positive lens and two negative lenses. Average of Abbe constants and average of partial dispersion ratios of positive lenses in the front first unit, average of Abbe constants and average of partial dispersion ratios of negative lenses in the front first unit, combined focal length of the positive lenses in the front first unit and focal length of the front first unit are appropriately set.

Abstract: A zoom lens includes, in order from an object side to an image side, first to fourth lens units having negative, positive, negative, and positive refractive power, respectively. During zooming from a wide-angle end to a telephoto end, at least the first, second, and third lens units move. The focal lengths of the first, second, and third lens units, the amount of movement of the second lens unit during zooming from the wide-angle end to the telephoto end, a lateral magnification at the wide-angle end of the second lens unit, a lateral magnification at the wide-angle end of the third lens unit, a lateral magnification at the telephoto end of the second lens unit, and the lateral magnification at the telephoto end of the third lens unit are appropriately set.

Abstract: An optical system comprises a first lens element and a second lens element which are respectively shiftable to have a component in a direction perpendicular to the optical axis, the second lens element being composed of the first lens element and other lens element, and the first lens element or the second lens element being shifted to have a component in a direction perpendicular to the optical axis, thereby carrying out a correction of the image plane. Thus, there are provided an optical system having a suitable vibration reduction property, an image apparatus equipped with the optical system and a method for manufacturing the optical system.

Abstract: A zoom lens includes a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power, in order from an object side to an image side, each lens unit moving during zooming, and the third lens unit moving toward the object side during focusing from an infinitely-distant object to a nearby object. A focal length f3 of the third lens unit, a composite focal length f12t of the first lens unit and the second lens unit at a telephoto end, a focal length fw of the entire system at a wide-angle end, and a focal length ft of the entire system at the telephoto end are appropriately set.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power. During zooming, a distance between every adjacent lens unit from the first to fourth lens units varies. A focal length fw of the entire zoom lens at a wide-angle end, a focal length f1 of the first lens unit, and a focal length f4 of the fourth lens unit are appropriately set according to predetermined mathematical conditions.

Abstract: A zoom lens includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a negative refractive power. The first to fourth lens units are arranged in order from the object side to the image side. All of the lens units are moved during zooming from the wide-angle end to the telephoto end. In the zoom lens, a number of lenses in each of the lens units, imaging magnifications on the telephoto end and the wide-angle end of the second lens unit and the third lens unit, a sum of thicknesses on the optical axis of the first lens unit and the second lens unit, and focal lengths of the entire zoom lens at a wide-angle end and at a telephoto end are appropriately set.

Abstract: A zoom lens and a zoom lens module are provided. The zoom lens is configured to form an image of an object at an object side onto an image plane at an image side. The zoom lens includes a first lens group, a second lens group, a third lens group and a fourth lens group disposed in sequence from the object side towards the image side. The refractive powers of the first lens group, the second lens group, and the third lens group are negative, positive, and negative, respectively. The zoom lens satisfies 1.90<|T1G/FW|<2.40. T1G is a distance of the first lens group along an optical axis of the zoom lens, and FW is an effective focal length of the zoom lens when the zoom lens is at a wide-end.

Abstract: There is provided a zoom lens including a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power, the lens groups being arranged in order from an object side to an image side. The second lens group includes a front group having positive refractive power, and a rear group having positive refractive power, the front and rear groups being arranged in order from the object side to the image side. The front group includes a positive lens, a positive lens, a negative lens, and a positive lens, the lenses being arranged in order from the object side to the image side. The rear group includes at least one positive lens.

Abstract: A zoom lens system comprising a negative first lens unit, a positive second lens unit, a negative third lens unit, and a positive fourth lens unit, wherein the first lens unit and the third lens unit move along an optical axis, and the fourth lens unit is fixed with respect to an image surface in zooming, the third lens unit moves along the optical axis in focusing, and the conditions: 0.0<|M3/fW|<0.5 and 0.2<|f3/f4|<1.0 (M3: an amount of movement of the third lens unit in zooming, f3: a composite focal length of the third lens unit, f4: a composite focal length of the fourth lens unit, fW: a focal length of the entire system at a wide-angle limit) are satisfied.

Abstract: A zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming from a wide-angle limit to a telephoto limit during image taking, wherein at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing from an infinity in-focus condition to a close-object in-focus condition in at least one zooming position, and among the focusing lens units, a lens unit having the absolute value, which is not the greatest absolute value, of a wobbling value at a wide-angle limit is a wobbling lens unit which senses a moving direction of the focusing lens units at the time of focusing by wobbling itself in a direction along the optical axis; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A zoom lens system according to the present invention includes a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with positive refractive power, and a fourth lens group with negative refractive power which are arranged in turn from the object side toward the image side, and the zoom lens system is formed so that, in performing a zooming operation from the wide angle end position to the telephoto end position, the first lens group keeps still, the distance between the first and second lens groups becomes small, the distance between the second and third lens groups becomes wide, and the distance between the third and fourth lens groups becomes small.

Abstract: A zoom lens system, in order from an object side to an image side, comprising a first lens unit having negative optical power, a second lens unit having positive optical power, a third lens unit having negative optical power, and a fourth lens unit having positive optical power, wherein the third lens unit moves along an optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and the conditions: 0.5<|f3/fW|<2.0 and 0.005<d3/fW<0.070 (f3: a focal length of the third lens unit, d3: an optical axial thickness of the third lens unit, fW: a focal length of the entire system at a wide-angle limit) are satisfied; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power, in which each lens unit moves during zooming from a wide-angle end to a telephoto end, and a focal length of the first lens unit, a focal length of the second lens unit, and a focal length of the entire zoom lens at the wide-angle end are appropriately set.

Abstract: There is provided a zoom lens which is suitable for a digital still camera and a video camera and includes a small number of lenses, especially a zoom lens which has an angle of view of 75° or more at the wide-angle end and a variable power ratio of about ×10. The zoom lens includes a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and, a fourth lens group with positive refractive power. The zoom lens varies power by changing an interval of each neighboring lens groups. The first lens group is composed of a negative lens and a positive lens. The third lens group is composed of an aperture stop, a cemented lens formed by a positive lens in a biconvex shape and a negative lens, and a positive lens.

Abstract: According to various aspects, an optical zoom lens system and a method magnifying an image using an optical zoom lens system are disclosed. In one example, the optical zoom lens system comprises a first lens group including a first focus-tunable lens and a first negative lens, a second lens group, positioned after the first lens group in an optical path, a third lens group, positioned after the second lens group in the optical path, and a fourth lens group, positioned after the third lens group in the optical path, including a second focus-tunable lens and a second negative lens.

Abstract: There is provided a zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. In zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group shortens, and a distance between the third lens group and the fourth lens group lengthens. The third lens group includes a single lens or a single cemented lens.

Abstract: There is provided a zoom lens including in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. In zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group narrows, and a distance between the third lens group and the fourth lens group widens. The third lens group includes a single lens or a single cemented lens.

Abstract: An image forming optical system comprising four or five lens groups in total, wherein during zooming from the wide angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the fourth lens group changes, the first lens group comprises three lenses including a negative meniscus lens, a positive meniscus lens, and a positive lens, the second lens group includes a negative meniscus lens having a convex surface directed toward the object side and a concave surface directed toward the image side, the negative meniscus lens being located closest to the object side in the second lens group, the position of the second lens group at the telephoto end is closer to the object side than that at the wide angle end, the image forming optical system has an aperture stop that moves integrally with the third lens group, the third lens group includ

Abstract: The invention provides a zoom lens, characterized by comprising, in order from an object side thereof, a first lens group of positive refracting power, a second lens group of negative refracting power, a third lens group of positive refracting power, and a fourth lens group of negative refracting power, upon zooming from a wide-angle end to a telephoto end of the zoom lens, a separation between the respective lens group changes, a separation between the first lens group and the second lens group becomes narrow, and a separation between the second lens group and the third lens group grows wide; upon focusing from a focusing-on-infinity state to a close-range focusing state, the fourth lens group moves in an optical axis direction; and Conditions (1) and (2) are satisfied at the wide-angle end.

Abstract: The present disclosure relates to a lens module, the module including a first lens having a positive (+) refractive power and capable of moving for zooming operation; a second lens having a negative (?) refractive power; a third lens having a positive (+) refractive power and having an inflection point at an image surface; and a fourth lens having a negative (?) refractive power.

Abstract: A zoom lens system includes a first unit having a positive refractive power, a second unit having a negative refractive power that moves for magnification-varying, a third unit having one of a positive refractive power and a negative refractive power that moves for magnification-varying, and a fourth unit having a positive refractive power.

Abstract: A zoom lens includes a first lens unit of a positive refractive power, a second lens unit of a negative refractive power, a third lens unit of a positive refractive power, and a fourth lens unit of a positive refractive power, wherein the first lens unit does not move for zooming, at least the second and fourth lens units are moved during zooming, the first lens unit includes at least one positive lens, and an Abbe number and a relative partial dispersion of a material of the positive lens, an average refractive index of materials of negative lenses included in the second lens unit, a movement amount of the second lens unit for zooming from a wide-angle end to a telephoto end, a focal length of the second lens unit, and a focal length of the entire zoom lens at the telephoto end are appropriately set.

Abstract: A zoom lens includes a first lens group having a positive refractive power, and a second lens group having a negative refractive power, an aperture stop, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power arranged in order from an object side, the third lens group having a first positive lens, a second positive lens, and a negative lens, and a third positive lens in order from the object side. When zooming from short to long focal end, the zoom lens is moved so that the interval between the first and second lens groups increases, that between the second and third lens groups decreases, that between the third and fourth lens groups increases, and the first and third lens groups are positioned closer to the object at the long focal end than the short focal end.

Abstract: A zoom lens includes, in a sequence from an object side to an image side, a first lens group having a negative refractive power and comprising two lenses; a second lens group having a positive refractive power; a stop disposed on the image side of the second lens group; and a third lens group having a positive refractive power, wherein: during zooming from a wide angle position to a telephoto position, an interval between the first lens group and the second lens group decreases, and an interval between the second lens group and the third lens group increases.

Abstract: A zoom lens includes a first lens unit having a negative refractive power and which is provided at a location closest to an object side, a lens unit LP having a positive refractive power, which is provided at a location closest to an image side, and which is stationary during zooming, and a lens unit LN having a negative refractive power, which is provided adjacent to the lens unit LP on the object side of the lens unit LP, and which is configured to move during zooming. In the zoom lens, optical parameters fp, fn, fw, ft, fni and ?dni are appropriately set.