Abstract: A zoom lens includes a first positive lens unit, a first negative lens unit, a stop, and a second positive lens unit, and at the time of zooming, the first positive lens unit is stationary, the first negative lens unit and the second positive lens unit move, and at the time of focusing, the first positive lens unit is stationary, and the first positive lens unit includes a reflecting member and a first positive lens unit object-side system, and the first positive lens unit-object side system is positioned on the object side of the reflecting member, and has a negative refractive power, and the following conditional expressions are satisfied. 3.7<ft/fw 1.55<|D1N/D2P|<2.5 1.75<|f2P/D2P|<2.

Abstract: The projection zoom lens substantially consists of a first lens group having negative refractive power, a second lens groups through a fourth lens group all having positive refractive power, a fifth lens group having positive or negative refractive power, and a sixth lens group having positive refractive power, arranged in this order from the magnification side; wherein the reduction side is telecentric. Further, the first lens group and the sixth lens group are fixed and the second lens group through the fifth lens group move along the optical axis while changing magnification. The fourth lens group substantially consists of only one positive meniscus lens with a concave surface toward the reduction side. The projection zoom lens satisfies conditional expression (1) below: 1.2<f3/f4<10.0??(1), where f3 is the focal length of the third lens group, and f4 is the focal length of the fourth lens group.

Abstract: A zoom lens includes: a first lens group having a negative refractive power; and a second lens group having a positive refractive power, provided in this order from an object side. Magnification is changed by moving the first lens group and the second lens group. The first lens group includes a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, and a fourth lens having a positive refractive power, provided in this order from the object side. The zoom lens satisfies the following conditional formulae, when fw is the focal length of the entire system at the wide angle end, f1 is the focal length of the first lens group, and f2 is the focal length of the second lens group: 0.00<fw/f2<0.43??(1-5) 0.56<|f1/f2|<2.00??(2-4).

Abstract: In a zoom lens in which a first lens group having a negative refractive power and a second lens group having a positive refractive power are disposed in order from the object side and zooming is performed by moving the first lens group and the second lens group, the first lens group is formed of a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, and a fourth lens having a positive refractive power, disposed in order from the object side. Then, when the focal length of the first lens group is taken as f1 and the focal length of the second lens group is taken as f2, the zoom lens is configured to satisfy a conditional expression give below: 0.00<|f1/f2|<1.04??(1-4).

Abstract: A zoom lens includes a positive first lens group, which is fixed during changing magnification and during focusing, a negative second lens group, which is moved during changing magnification, a positive third lens group, which is fixed during changing magnification and during focusing, a positive fourth lens group, which is moved during changing magnification and during focusing, and a negative fifth lens group, which is moved during changing magnification, which are in this order from an object side. A lens group constituting the first lens group consists of a negative front group and a positive rear group in this order from the object side. The second lens group consists of four lenses of a negative lens, a positive lens, a negative lens, and a positive lens or a negative lens arranged in this order from the object side.

Abstract: A zoom lens includes a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group and a sixth lens group, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens group is with positive refractive power. The second lens group is with negative refractive power. The third lens group is with positive refractive power. The fourth lens group is with negative refractive power. The fifth lens group is with positive refractive power. The zoom lens satisfies the following condition: |fw/f6<0.15, wherein fw is an effective focal length of the zoom lens at a wide-angle end and f6 is an effective focal length of the sixth lens group.

Abstract: A zoom lens device includes a focusing lens group arranged on an object side, and a variator lens group next thereto, and a temperature sensor. The focusing lens group includes a focusing lens, and a temperature-based correction lens for correcting changes in focal point caused by temperature changes around the focusing lens group. The temperature-based correction lens is moved by a temperature-based correction lens driving mechanism along an optical axis to a position determined by a temperature detected by the temperature sensor, independently of the positions of the focusing lens or variator lens group. Thereby, the zoom lens device is capable of favorably correcting defocus of the lens group caused by an ambient temperature change with a simple correcting mechanism.

Abstract: A zoom lens includes in order from an object side, 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 positive refractive power, and at the time of zooming, the first lens unit moves, and the zoom lens satisfies the following conditional expressions (1-1a), (1-2a), and (1-3a). 0.43<(?2T/?2W)/(?3T/?3W)<0.68??(1-1a) 0.4<(?1G/f1)/(?4G/f4)<2.3??(1-2a) 2.1<f3/fW<4.

Abstract: A zoom lens includes, from the object side, a positionally-fixed first lens group having a positive refracting power, a second lens group having a negative refracting power and movable in an optical axis direction for zooming, a third lens group having a positive refracting power, and a fourth lens group movable in the optical axis direction. The first lens group includes a negative lens, a positive lens and another positive lens disposed in order from the object side and satisfies 15.0<ft/fw<31.0??(1) 7.0<f1/fw<13.0??(2) ?8.5<fL1/fw<?4.0??(3) where fw and ft are the focal lengths of the entire lens system in a wide angle end state and a telephoto end state, respectively, f1 is the focal length of the first lens group, and fL1 is the focal length of the negative lens of the first lens group.

Abstract: A zoom lens includes a lens unit Ln having negative refractive power including two or less lenses moving during focusing and zooming, a lens unit Lp1 having positive refractive power disposed adjacent to an object side thereof, and a lens unit Lp2 having positive refractive power disposed adjacent to an image side thereof. The lens units Lp1 and Lp2 move during zooming. A distance Tlw between a lens surface nearest to the object side in the entire zoom lens and an image plane at a wide-angle end, a distance Dnw between the lens surface nearest to the image side of the lens unit Ln and the image plane at the wide-angle end, a back focus bfw at the wide-angle end, and a maximum amount of movement Mnz during focusing of the lens unit Ln at a telephoto end are appropriately set.

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, an aperture stop, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and fifth lens group. The zoom lens further satisfies given conditions.

Abstract: A zoom lens including a first lens unit having a positive refractive power, a second lens unit having a negative reflective power, a third lens unit having a positive refractive power, and a rear lens group including one or more lens units in this order from an object side to an image side, wherein distances between the respective lens units vary during the zooming operation, wherein the first lens unit consists of three lenses including one negative lens, and a partial dispersion ratio of a material for the negative lens of the first lens unit, an Abbe number of the same, a focal length of the entire system at a wide angle end and a focal length of the first lens unit are set individually and adequately.

Abstract: A zoom lens includes, in order from an object side to an image side, first to fifth lens units respectively having positive, negative, positive, negative, and positive refractive powers. During zooming from a wide-angle end to a telephoto end, each of the lens units moves in such a way that a distance between the first and second lens units increases, a distance between the second and third lens units decreases, a distance between the third and fourth lens units increases, and a distance between the fourth and fifth lens units increases. The distances D34w and D34t between the third and fourth lens units, the distances D45w and D45t between the fourth and fifth lens units, focal lengths fw and ft of the entire zoom lens, and focal lengths f1 and f4 of the first and fourth lens units are appropriately set.

Abstract: A zoom lens includes an external frame, a rotary shaft, an internal frame, a lens group and a spring. The internal frame is connected to the external frame via the rotary shaft, so that the internal frame is rotatable relative to the external frame. The lens group is fixed in the internal frame. The spring comprises a deformation part and two extension parts extended from the deformation part, wherein one extension part is propped against the internal frame and inclined at an acute angle relative to the rotary shaft, and the other extension part is propped against the external frame.

Abstract: A zoom lens including, in order from an object side, positive, negative, positive, positive, and positive lens units, or positive, negative, positive, positive, positive, and positive lens units. 1.5<L2fm/L2W<500; ?30<f3/f2<?3; and ?15<f1/f23W<?8 are satisfied, where fm=fw×(Z)1/2, fw represents a local length of the entire system at a wide angle end, Z represents a zoom ratio, L2W represents an interval between a second and third lens units at the wide angle end, L2fm represents an interval between the second and third lens units at a zoom position at which an offaxial principal ray having a largest enrage height is highest in a zoom range from the wide angle end to the focal length fm, f1, f2 and f3 respectively represent focal lengths of the first, second, and third lens units, and f23W represents a combined focal length of the second and third lens wait at the wide angle end.

Abstract: A zoom lens system is composed of negative, positive, negative, and positive lens groups, of which at least the first to third move during zooming. During zooming from the wide-angle end to the telephoto end, the distance between the first and second lens groups decreases, the distance between the second and third lens groups varies, and the distance between the third and fourth lens groups increases. The conditional formulae 1.0?|f2/f1|?1.5 and 2.0?|f4/f1|?5.0 are fulfilled (f1, f2, and f4 representing the focal lengths of the first, second, and fourth lens groups).

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 second lens unit is composed of an object-side second lens unit and an image-side second lens unit, the object-side second lens unit has positive optical power, an aperture diaphragm is located between the object-side second lens unit and the image-side second lens unit, and the conditions: ?0.5<f2O/f2I<1.0 and 0.12<d2O/fW<0.35 (f2O: a composite focal length of the object-side second lens unit, f2I: a composite focal length of the image-side second lens unit, d2O: an optical axial distance from a most object side lens surface of the object-side second lens unit to the aperture diaphragm, fW: a focal length of the entire system at a wide-angle limit) are satisfied.

Abstract: A wide angle lens system includes a first lens group having a negative refractive power and a second lens group having a positive refractive power arranged from an object side. The first lens group includes a first lens of a meniscus shape having a convex surface toward the object side, a second lens having a concave surface toward the object side, and a third lens having a convex surface toward the object side, and the second lens group includes a fourth lens having a convex surface toward the object side, a fifth lens having a concave surface toward the object side, and a sixth lens of a meniscus shape having a concave surface toward the object side. A photographing apparatus includes the wide angle lens system.

Abstract: A zoom lens includes, in order from object side, a positive first lens unit which does not move for varying magnification, a negative second lens unit which moves for varying magnification, a negative third lens unit which moves for varying magnification, and a positive fourth lens unit which does not move for varying magnification, wherein the first lens unit includes a positive lens which satisfies the following conditions: 70<?p<85; 2.31<Np+0.01×?p<2.58; and 1.6<Np<1.85, where Np is refractive index of the positive lens, and ?p is Abbe constant of the positive lens, and 1.25<|fp/fna|<1.7 is satisfied, where fp is focal length of the positive lens, and fna is combined focal length of negative lenses in the first lens unit defined by the equation: fna = 1 ? i = 1 n ? 1 fn i , where n is a number of the negative lenses in the first lens unit, and fni is focal length of the i-th negative lens.

Abstract: The zoom lens comprises five or more groups of lens pieces, namely, the foremost or first lens group of positive refractive power located the closest to an object, the succeeding second lens group of negative refractive power, the third lens group of positive refractive power, the fourth lens group of positive refractive power, and the fifth lens group all arranged in this order, and if any, the rearmost lens group(s) closer to the imaging plane than the fifth lens group. The zoom lens meets requirements as defined in the formula regarding a synthetic optical power of the fifth lens group and, if any, the rearmost lens group(s) closer to the imaging plane than the fifth lens group while the zoom lens is taking a posture of 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: The zoom lens comprises the foremost or first lens group of positive refractive power located the closest to an object, the succeeding second lens group of negative refractive power, and the third lens group of positive refractive power, all arranged in this order, and if any, the rearmost lens group(s) closer to the imaging plane than the third lens group, all or part of the lens group(s) of negative refractive power behind the third lens group being moved in directions normal to the optical axis to serve as an anti-vibration lens for shifting an image. The zoom lens meets requirements as defined in the formula regarding a displacement of the first lens group, a focal length of the zoom lens at the wide-angle end, a focal length of the zoom lens at the telephoto end, and a focal length of the first lens group.

Abstract: A zoom lens and a photographing apparatus having the zoom lens are provided. The 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 including a shutter and having a positive refractive power; a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power, wherein the first, second, third, fourth, fifth, and sixth are arranged from an object side toward an image side, and when the zoom lens zooms from a wide angle position to a telephoto position, the third lens group is fixed, and the first, second, fourth, fifth, and sixth lens groups are moved.

Abstract: A zoom lens includes an aperture stop and a plurality of lens units which are moved during zooming. The plurality of lens units includes, on an object side of the aperture stop, a lens unit Lp having a positive refractive power and a lens unit Ln having a negative refractive power which is disposed to be adjacent to an image side of the positive lens unit Lp. At least one of the positive lens unit Lp and the negative lens unit Ln includes two or less lenses which are moved during focusing, and a focal length Fp of the positive lens unit Lp and a focal length Fn of the negative lens unit Ln are appropriately set based on predetermined mathematical conditions.

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: A projection zoom lens includes a front lens group, a rear lens group, and an aperture stop. The front lens group has negative refractive power and is disposed adjacent to an object side of the projection zoom lens. The front lens group includes a first lens group, a second lens group, and a third lens group. The rear lens group has positive refractive power and is disposed adjacent to an image side of the projection zoom lens. The rear lens group includes a fourth lens group, a fifth lens group, and a sixth lens group. The aperture stop is disposed between the front lens group and the rear lens group. The third lens group, the fourth lens group, and the fifth lens group move along an optical axis of the projection zoom lens to change an effective focal length of the projection zoom lens when the projection zoom lens zooms.

Abstract: A zoom lens includes: a first lens group having positive refracting power; a second lens group having negative refracting power; a third lens group having positive refracting power; a fourth lens group having positive refracting power; and a fifth lens group having positive refracting power arranged in this order from an object side toward an image side, wherein when the zoom lens undergoes zooming operation from a wide-angle end toward a telescopic end, the first lens group moves away from the second lens group toward an object to be imaged, the third lens group approaches the second lens group toward the object, and the fourth lens group approaches the third lens group toward the object, and the zoom lens satisfies the following conditional expression (1) 4.5<100×D(T,2?3)/fW<15??(1).

Abstract: A zoom lens includes, sequentially from an object side, a positive first lens group, a negative second lens group, a positive third lens group, and a positive rear lens group. During zooming from a wide angle position to a telephoto position, an interval between the first lens group and the second lens group increases, and an interval between the second lens group and the third lens group decreases. The rear lens group includes a positive first sub-group, a negative second sub-group, and a positive third sub-group, and focusing is performed by moving the second sub-group toward an image surface side. The zoom lens satisfies the following conditions: 0.2<frt/ft<1.8 and 0.2<|fb|/frt<1.0, where “frt” denotes a focal length of the rear lens group at the telephoto position, “fb” denotes a focal length of the second sub-group, and “ft” denotes a focal length of the zoom lens at the telephoto position.

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: A variable-magnification optical-system substantially consists of a first-lens-group having positive-refractive-power, a second-lens-group having negative-refractive-power, a third-lens-group having negative-refractive-power, a fourth-lens-group having negative-refractive-power, an aperture-stop, and a fifth-lens-group having positive-refractive-power in this order from an object-side along an optical-axis. The second-lens-group, third-lens-group and fourth-lens-group move when magnification is changed from a wide-angle-end to a telephoto-end.

Abstract: In a zoom lens system, an optical apparatus, and a manufacturing method, there are provided, in order from an object side: a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, a fourth lens group having negative power, a fifth group having positive power, and an aperture stop disposed to an image side of the second lens group. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens and second lens groups increases, a distance between the second and third lens groups decreases, a distance between the third and fourth lens groups varies, and a distance between the fourth and fifth lens groups varies. With given conditions being satisfied, high optical performance with suppressing variation in aberrations are achieved.

Abstract: A variable magnification optical system includes a relay lens group (a fifth lens group) substantially consisting of a relay front group and a relay rear group with a predetermined air space therebetween, and which is fixed during magnification change and has image formation action, and an extender lens group insertably and detachably arranged between the relay front group and the relay rear group, and which extends a focal length toward a telephoto side without changing an image formation position. The extender lens group substantially consists of a first lens group having positive refractive power and a second lens group having negative refractive power in this order from an object side. The second lens group is a cemented lens substantially consisting of a convex meniscus lens, a biconcave lens and a convex meniscus lens in this order from the object side.

Abstract: A zoom lens includes, in order from the object side to the image side along its optical path, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power and including a prism reflecting member, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power, wherein the distances between the lens units vary during zooming from the wide angle end to the telephoto end, the first lens unit and the third lens unit are located closer to the ray incidence side at the telephoto end than at the wide angle end, the position of the second lens unit is fixed during zooming from the wide angle end to the telephoto end.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a rear lens group including lens units and as a whole having a positive refractive power. Distances between the lens units change during zooming. The second lens unit includes, in order from the object side to the image side, a negative lens component and a cemented lens including a negative lens component and a positive lens component. The second lens unit includes at least five lens components. A focal length f1 of the first lens unit, a focal length f2 of the second lens unit, a refractive index Ndp of the positive lens component of the cemented lens, and a refractive index Ndn of the negative lens component of the cemented lens are set appropriately.

Abstract: The present invention relates to a zoom lens which can shift images using a movable optical system so as to have components orthogonal to the optical axis, and can correct hand motion blur, and minimizes the deterioration of performance while attempting higher variable power. This zoom lens has, 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 negative refractive power, and a fifth lens group G5 having positive refractive power, and at least a part of the fourth lens group G4 can move so as to have components orthogonal to the optical axis, and a distance between each lens group is changed upon zooming from a wide-angle end state to a telephoto end state, and the following conditional expression is satisfied, 0.01<f5/ft<0.

Abstract: A zoom lens system including, in an order from an object to an image: a first lens group having negative refractive power; and a second lens group having positive refractive power, wherein the zoom lens system satisfies equations: i) 1.2?Fnow?2.2; ii) 2.5<ft/fw?3; and iii) BFL?6 mm, where Fnow denotes an F-number at a wide angle position, ft and fw respectively denotes overall focal lengths at a telephoto position and the wide angle position, and BFL denotes a back focal length.

Abstract: A zoom lens includes, in order from an object side to an image side: a first lens unit having positive refractive power, which does not move for zooming, the first lens unit including a lens unit which moves for focusing; a second lens unit having negative refractive power for magnification variation; a third lens unit having negative refractive power, which moves for zooming; a fourth lens unit having positive refractive power, which moves for zooming; and a fifth lens unit having positive refractive power, which does not move for zooming, in which an interval between the fourth lens unit and the fifth lens unit becomes largest at a telephoto end, and lateral magnifications ?2w and ?2t of the second lens unit at a wide-angle end and at the telephoto end are respectively set appropriately.

Abstract: A zoom lens comprising, in order from the object side to the image side 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, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power, wherein the first lens unit is located closest to the object side, the fifth lens unit is located closest to the image side, during zooming from the wide angle end to the telephoto end, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit move, the fifth lens unit is stationary, and the distances between the lens units vary, the third lens includes a positive lens, and the zoom lens satisfies the following condition (1): 72<?3p<110??(1).

Abstract: A zoom lens includes in order 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, and a last lens group having a positive refractive index, and at the time of zooming from the wide angle end to the telephoto end, the first lens group is fixed, the second lens group moves toward a side of an image plane, the third lens group is fixed, and the fourth lens group moves, and at the time of focusing, the fourth lens group moves. The zoom lens satisfies the following conditional expression (101) 0.20<log(?34T/?34W)<0.9·log ???(101).

Abstract: The image pickup system includes a camera and an interchangeable lens having an image-taking optical system. The camera includes an image sensor to photoelectrically convert an object image formed by the image-taking optical system and to be moved in an optical axis direction, and a camera controller configured to control movement of the image sensor such that focus variation caused due to variation of magnification of the interchangeable lens is reduced. The camera controller is configured to acquire image sensor moving data corresponding to the interchangeable lens attached to the camera, and controls the movement of the image sensor by using the image sensor moving data.

Abstract: An embodiment of this invention provides a zoom lens, which primarily includes, in order from an object side to an image-forming side, 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; a fifth lens group having negative refractive power; and a sixth lens group having positive refractive power; wherein the first lens group comprises a prism, and the second lens group, the fourth lens group, and the fifth lens group are moved toward the third lens group along an optical axial for zooming from a wide-angle end to a telephoto end.

Abstract: A zoom lens system comprising a plurality of lens units, wherein a lens unit located closest to an object side and a lens unit located closest to an image side are fixed with respect to an image surface in zooming from a wide-angle limit to a telephoto limit at a time of image taking, and at least three lens units among all the lens units are moving lens units that move along an optical axis in the zooming, at least one lens unit among the moving lens units is a focusing lens unit that moves along the optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and the following condition: ?(Tn)/H?2.1 (?(Tn): the total of axial thicknesses of all the moving lens units, H: the maximum image height) is satisfied.

Abstract: A zoom lens includes a front lens group including a first lens unit and a second lens unit, a reflecting mirror configured to bend an optical path, and a rear lens group including two or more lens units. When the zoom lens is retracted, the reflecting mirror performs at least one of rotation and linear movement to provide space for the front lens group. A focal length of a lens unit having the highest absolute value of refractive power among negative lens units in the front lens group, a focal length of the entire zoom lens at a telephoto end, a maximum value and a minimum value of amounts of movement of the at least two lens units in the rear lens group during zooming, a length of a reflecting surface of the reflecting mirror, and a maximum effective diameter of the first lens unit are appropriately set.

Abstract: During zooming from the wide angle end to the telephoto end, the distance between the first lens unit having a positive refractive power and the second lens unit having a negative refractive power, the distance between the second lens unit and the third lens unit having a positive refractive power, and the distance between the third lens unit and the fourth lens unit having a negative refractive power vary. In zooming from the wide angle end to the telephoto end, the first lens unit is located closer to the object side at the telephoto end than at the wide angle end. The first lens unit consists of two lenses including a negative lens and a positive lens. The first lens unit has at least one aspheric surface in the optical path. The zoom lens satisfies the following conditional expression (1): 0.5<(LTLt/?rear)/FLG1<1.0??(1).

Abstract: A particle manipulation system and a projection device are provided. The projection device includes an image source and a projection lens. The image source provides an image beam. The projection lens is disposed on a light path of the image beam and includes a zoom lens set and a focusing lens set. The zoom lens set is disposed on the light path of the image beam from the image source and includes at least two lens groups disposed in sequence on the light path of the image beam. The focusing lens set is disposed on the light path of the image beam. The zoom lens set is disposed between the image source and the focusing lens set. A photoconductor chip is disposed on the light path of the image beam from the projection lens.

Abstract: A zoom lens includes, in order from an object side to an image side, a first, a second, a third, a fourth, a fifth, a sixth and a seventh lens units respectively having positive, negative, positive, negative, positive, negative and positive refractive powers. A distance between adjacent lens units change during zooming so that a distance between the fourth lens unit and the fifth lens unit at a telephoto end is shorter than the distance at a wide angle end and a distance between the fifth lens unit and the sixth lens unit at the telephoto end is longer than the distance at the wide angle end. And the fourth lens unit moves during focusing.

Abstract: The zoom lens has an aperture stop arranged between the second lens unit and the fourth lens unit. During zooming from the wide angle end to the telephoto end, the distances between the lens units vary in such a way that the distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, the distance between the second lens unit and the third lens unit is smaller at the telephoto end than at the wide angle end, and the distance between the fourth lens unit and the fifth lens unit is larger at the telephoto end than at the wide angle end. The zoom lens satisfies the following conditional expression (1): 3.5?LTLw/IHt?8.9??(1).

Abstract: In a zoom lens of a fixed total length, at the time of changing the magnification from the wide-angle end toward the telephoto end, the first lens group is anchored while the second lens group is moved, and the third and fourth lens groups are moved so as to be located at the object side of the telephoto end relative to the wide-angle end, such that: the interval between the second and third lens groups is decreased at the telephoto end relative to the wide-angle end; the interval between the third and fourth lens groups is increased at the telephoto end relative to the wide-angle end; and the interval between the fourth and fifth lens groups is increased at the telephoto end relative to the wide-angle end, and at the time of focusing a near object point from a remote object point, the second lens group is moved.

Abstract: A zoom lens system has a combined focal length fw at the wide angle end and includes, in order from an object side, a first lens group with positive refractive power and combined focal length f1; 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 with positive refractive power and including, in order from the object side, a negative biconcave lens with focal length f51 and a positive biconvex lens with focal length f52, the negative biconcave lens and the positive biconvex lens disposed with an air space shorter than a center thickness of the negative biconcave lens in between and both surfaces of the positive biconvex lens being aspherical. The system satisfies the following conditions: 13.5<f1/fw<17.5, and 1.0<|f51/f52|<1.5.

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.