Abstract: A variable magnification projection optical system includes, in order from an enlargement side: a first lens group having negative refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power. During zooming, the first lens group is fixed, and the second lens group and the third lens group move. The second lens group includes a plurality of lenses each having positive refractive power. All lenses each having positive refractive power in the first lens group and the second lens group are made of a glass material having a transmittance greater than 0.98 per thickness of 10 mm with respect to light having a wavelength of 440 nm.

Abstract: A variable magnification optical system comprising a plurality of lens groups which includes a first positive lens group disposed at a most object side and having positive refractive power, a first negative lens group disposed at an image side of the first positive lens group and having negative refractive power, and a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the first negative lens group further including a lens that satisfies predetermined conditional expression(s), thereby various aberrations being corrected superbly, and vibration reduction lens group being made small in size.

Abstract: A photographing lens system includes, in order from an object side to an image side along an optical path, a front lens group and a rear lens group. The front lens group includes four lens elements. The rear lens group includes four lens elements. A second lens element counted from the image side in the front lens group has negative refractive power. An image-side surface of a first lens element counted from the image side in the front lens group is convex in a paraxial region thereof. A second lens element counted from the object side in the rear lens group has negative refractive power. An object-side surface of a first lens element counted from the image side in the rear lens group is concave in a paraxial region thereof. At least one lens element in the rear lens group has at least one lens surface being aspheric.

Abstract: A laser processing head transmits a laser beam to a process zone. An input lens fixedly mounted in the head images the beam from an input with a first (negative) focal length along an optical axis. An intermediate lens is movably mounted in the head in connection with an actuator, which can move the intermediate lens along the axis at a variable lens distance relative to the input lens. The intermediate lens images the beam with a second (positive) focal length. An output lens fixedly mounted in the head images the beam with a third (positive) focal length along the axis to a focal point. The third focal length is greater than the second focal length and provides a large working distance. The focal point can be varied at a variable focal distance along the axis in relation to the variable lens distance by which the intermediate lens is moved.

Abstract: A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens, all of which are arranged in order from an object side to an image side along an optical axis. The first, second, seventh, and eighth lenses are with refractive power. The third lens is with negative refractive power and includes a concave surface facing the object side. The fourth lens is with positive refractive power. The fifth lens is with positive refractive power and includes a convex surface facing the object side. The sixth lens is with positive refractive power and includes a convex surface facing the image side. The ninth lens is with positive refractive power and includes a convex surface facing the object side. An air gap is disposed between the sixth lens and the seventh lens.

Abstract: A projection zoom lens is configured by a first group having a negative refractive force, a second group having a positive refractive force, a third group having a positive refractive force, an aperture diaphragm, a fourth group having a positive refractive force, and a fifth group having a positive refractive force. The groups are arranged in aforementioned order from an enlarged-side to a reduced-side in the projection zoom lens, wherein the reduced-side is telecentric, wherein the first group is configured by a first sub-lens group having a positive or a negative refractive force, a second sub-lens group having a negative refractive force, and a third sub-lens group having a negative refractive force, wherein the sub-lens groups are arranged sequentially from the enlarged-side to form a focusing group, wherein the second group to the fifth group constitute a zooming group.

Abstract: A lens assembly includes a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a reflective element. 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 reflective element includes a reflective surface. A light from an object side sequentially passes through the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group to a second side. The reflective element is disposed between a first side and the second side. Intervals of the lens groups are changeable, so that the lens assembly can change the effective focal length.

Abstract: A photographing lens system, a photographing device and an electronic apparatus are provided. The photographing lens system includes a first lens group and a second lens group in sequence from an object side to an image side. The first lens group includes N lenses, and N is an integer greater than 2. In a direction from the object side to the image side, lens one in the first lens group is a first lens, and lens N in the first lens group is a second lens. The first lens is a lens with a positive focal power, and the second lens is a lens with a focal power. The second lens group includes at least one lens with a focal power. An air gap between the first lens group and the second lens group is changed in the process of focusing between an infinite distance and a closer distance.

Abstract: A lens module includes: a first lens having negative refractive power; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having negative refractive power; a fifth lens of which an object-side surface is concave; and a sixth lens having one or more inflection points on an image-side surface thereof, wherein the first to sixth lenses are sequentially disposed from an object side of the lens module to an image side of the lens module.

Abstract: An image sensing device includes a first light path changing element, a second light path changing element, and a plane lens. The first light path changing element includes a first light-incident side and a first light-emergent side, where the first light-incident side faces an image-capturing direction, the first light-emergent side faces a zoom optical axis, and there is an angle between the first light-incident side and the first light-emergent side. The second light path changing element includes a second light-incident side and a second light-emergent side, where the second light-incident side faces the zoom optical axis, the second light-emergent side faces an image-forming direction. An angle is between the second light-incident side and the second light-emergent side. An image-capturing light path passes through the first light-incident side, the first light-emergent side, the second light-incident side, and the second light-emergent side. The plane lens is disposed on the image-capturing light path.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens sequentially disposed from an object side. The optical imaging system satisfies |Pnu|[10?6° C.?1 mm?1]?30, where Pnu is ?Pnui in which i=1, 2, . . . , 7, Pnui is 1/(vti·fi), vti is [DTni/(ni?1)?CTEi]?1, fi is an effective focal length of an i-th lens, ni is a refractive index of the i-th lens, DTni is a rate (dni/dT) of change of the refractive index according to a temperature of the i-th lens, and CTEi is a thermal expansion coefficient of the i-th lens.

Abstract: This zoom optical system (ZL(1)) has a plurality of lens groups (G1-G7), wherein when during zooming, distances between adjacent lens groups vary. The plurality of lens groups include: a first focused lens group (G6) that moves during focusing; and a second focused lens group (G7) that is disposed closer to an image plane side than the first focused lens group and moves during focusing along a trajectory that is different from that of the first focused lens group. The first focused lens group (G6) and the second focused lens group (G7) both have a negative refractive power and satisfy the following conditional expression, 0.40<fF1/fF2<6.00, where fF1: focal length of first focused lens group and fF2: focal length of second focused lens group.

Abstract: A variable power optical system (ZL (1)) includes a plurality of lens groups (G1-G7). During variable magnification, an interval between adjacent lens groups changes. The plurality of lens groups include: a first focusing lens group (G5) that moves during focusing; and a second focusing lens group (G6) that is disposed more toward an imaging surface side than the first focusing lens group and that moves along a different trajectory than the first focusing lens group during focusing. The first focusing lens group and the second focusing lens group both have a negative refractive power. The plurality of lens groups satisfy the following condition: 0.40<fF1/fF2<3.50 (wherein fF1 is the focal distance of the first focusing lens group, and fF2 is the focal distance of the second focusing lens group).

Abstract: A zoom lens is provided. The zoom lens may include in order from an object side to an image side: a first lens group; a second lens group; a third lens group; a fourth lens group; and a fifth lens group; wherein the zoom lens satisfies the following conditions: ?1.7?f2/fw???0.3, 0.7?f3/fw??2.1, 1.1?f4/fw??2.5, and TTL/fw??6.5, wherein f2 denotes a focal length of the second lens group, f3 denotes a focal length of the third lens group, f4 denotes a focal length of the fourth lens group, fw? denotes a focal length of the zoom lens, and TTL denotes a total track length of the zoom lens.

Abstract: A variable magnification optical system comprising a plurality of lens groups which includes a first negative lens group having negative refractive power, a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power, a third negative lens group disposed at a more image side than the second negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the predetermined conditional expression(s) being satisfied. The variable magnification optical system can attain a high optical performance and be made in small in size.

Abstract: A zoom optical system (ZL) comprises, in order from an object: 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 subsequent lens group (GR), wherein upon zooming, a distance between the first lens group (G1) and the second lens group (G2) changes, a distance between the second lens group (G2) and the third lens group (G3) changes, and a distance between the third lens group (G3) and the subsequent lens group (GR) changes, the subsequent lens group (GR) comprises a focusing lens group that moves upon focusing, and the second lens group (G2) comprises a partial group that satisfies following conditional expressions, 1.40<fvr/f2<2.30, 1.80<f1/fw<3.

Abstract: The zoom optical system according to one embodiment of the present invention comprises a first lens group, a second lens group, and a third lens group which are serially arranged from the object-side towards the image-side, wherein the first lens group comprises a plurality of fixed lenses, the second lens group comprises two movable lenses, the third lens group comprises two movable lenses, magnification is adjusted according to the movement of the second lens group, focus is adjusted according to the movement of the third lens group, the focal length at maximum magnification is at least 13 mm, and the f-number at maximum magnification is at most 3.7.

Abstract: An optical system (LS) has an aperture stop (S), and a negative lens (L73) disposed closer to the image side than the aperture stop (S) and satisfying the following conditional expressions. ?0.010<ndN2?(2.015?0.0068×?dN2), 50.00<?dN2<65.00, 0.545<?gFN2, ?0.010<?gFN2?(0.6418?0.00168×?dN2) where ndN2 is the refractive index to the d line of the negative lens, ?dN2 is the Abbe number with respect to the d line of the negative lens, and ?gFN2 is the partial dispersion ratio of the negative lens.

Abstract: A zoom lens includes a first lens group and a second lens group. A relative movement between the first lens group and the second lens group is allowed, whereby the zoom lens zooms between a wide-angle end and a telephoto end. While the zoom lens is switched from the wide-angle end toward an intermediate state, the first lens group is moved toward the image side. While the zoom lens is switched from the intermediate state toward the telephoto end, the first lens group is moved toward the object side.

Abstract: There is provided an optical imaging system including a prism, a first fixed lens group, a first movable lens group, a second movable lens group, and a second fixed lens group. The prism is configured to refract light reflected from an object side toward an imaging plane and a reflecting member. The prism is disposed on the first fixed lens group and the first movable lens group is configured to change a position of the imaging plane so that an overall focal length is changed. The second movable lens group is configured to adjust a position of the imaging plane so that a focal length for an object is adjusted. The imaging plane is disposed on the second fixed lens group.

Abstract: A zoom optical system comprises, in order from an object: a first lens group (G1) having positive refractive power; a second lens group (G2) having negative refractive power; and a subsequent group (GR) including at least one lens group. Upon zooming, distances between the first lens group (G1) and the second lens group (G2) and between the second lens group (G2) and the subsequent group (GR) change. The subsequent group (GR) comprises a focusing group (Gfc) having negative refractive power for focusing. The first lens group (G1) comprises a 1-1st lens that has positive refractive power and is disposed closest to the object. A following conditional expression is satisfied: 0.20<f1/fR<0.85 where, f1 denotes a focal length of the first lens group, and fR denotes a focal length of a lens component, in the subsequent group, closest to an image surface.

Abstract: A zoom lens consisting of, in order from an object side to an image side: a first lens group that has a positive refractive power; a second lens group that has a negative refractive power; an intermediate lens group that consists of one or two lens groups; and a final lens group, wherein during zooming, the second lens group moves along an optical axis, and all distances between adjacent lens groups change.

Abstract: A zoom lens includes, in order from an object side to an image side, first, second and third lens units having positive, negative and positive refractive powers. The first lens unit moves during zooming. During zooming from a wide-angle end to a telephoto end, a distance between the first and second lens units widens, and a distance between the second and third lens units narrows. The first lens unit consists of three or less lenses. The second lens unit consists of, in order from the object side to the image side, a first single lens as a spherical lens having a negative refractive power, a cemented lens in which a lens having a negative refractive power and a lens having a positive refractive power are cemented, and a second single lens as a spherical lens having a negative refractive power. A predetermined condition is satisfied.

Abstract: A zoom optical system includes a positive first lens group, a negative second lens group disposed on an image side of the first lens group, a positive third lens group disposed on an image side of the second lens group, a negative fourth lens group disposed on an image side of the third lens group, and a final lens group disposed on an image side of the fourth lens group and closest to an image. During zooming, distances between lens groups change, and the first lens group moves along an optical axis. A negative focusing lens group is provided, and the final lens group is disposed on an image side of the focusing lens group. A negative vibration proof group of the second lens group may include, in order from an object, a negative lens, an air gap and a cemented lens of a negative lens and a positive lens. The final lens group may have negative refractive power.

Abstract: The present invention relates to optical imaging systems which are able to provide increased depth of field to microscope devices, motion-picture cameras, and still photographic cameras. Optical systems described herein are able to provide the increased depth of field while maintaining wide field of view and reducing spherical aberration and distortion. Optical systems described herein are also able to be used with standard film and digital sensor formats, and are able to be attached to, or integrated with, photographic and motion-picture cameras, including currently existing cameras.

Abstract: The variable magnification optical system consists of a positive first lens group, an intermediate group, and a subsequent group in order from an object side to an image side, and does not form an intermediate real image in the entire zooming range. During zooming in a first zooming mode, a distance between the first lens group and the intermediate group changes, all distances between adjacent lens groups in the intermediate group change, a distance between the intermediate group and the subsequent group changes, and all distances between adjacent lens groups in the subsequent group are stationary. During zooming in the second zooming mode, all lens groups in the first lens group and the intermediate group are stationary, and all the distances of the adjacent lens groups in the subsequent group change. The zooming in the first zooming mode and the zooming in the second zooming mode can be independent.

Abstract: A zoom lens consists of, in order from an object side, a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group. The first lens group consists of, in order from the object side, a first A lens group that does not move during focusing, a first B lens group that moves during focusing, and a first C lens group that does not move during focusing. During zooming, the first lens group and the fifth lens group do not move, and the second lens group, the third lens group, and the fourth lens group move. The fourth lens group includes a stop. The zoom lens satisfies a predetermined conditional expression.

Abstract: A zoom lens includes, 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 positive power; a fifth lens group having negative power; and a sixth lens group having positive power. The fourth lens group includes at least one positive lens that satisfies a conditional formula of vdp?65. A conditional formula of 1.19?f3/ft?4.15 and a conditional formula of 0.51?f4/ft?1.50 are satisfied.

Abstract: A zoom lens consists of, 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, a third lens unit having a positive refractive power, and a rear unit that includes a plurality of lens units. All lens units move during zooming, and a distance between adjacent lens units changes. The third lens unit includes, in order from the object side to the image side, a first subunit having a positive refractive power, a second subunit having a positive refractive power, and a third subunit having a positive refractive power. The second subunit includes a negative lens and a positive lens. The second subunit moves in a direction having a component orthogonal to an optical axis during an image stabilization. A predetermined condition is satisfied.

Abstract: The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression is related to lateral magnification of the fourth lens group and a lateral magnification of the sixth lens group is satisfied.

Abstract: A modular finite conjugate zoom lens assembly with five lens groups each including a doublet, wherein two or three movable lens groups are disposed between a pair of static lens groups.

Abstract: The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression is related to lateral magnification of the fourth lens group and a lateral magnification of the sixth lens group is satisfied.

Abstract: A zoom lens consists of in order from an object side to an image side: a first lens unit having a positive refractive power and configured not to move for zooming; three or four moving lens units configured to move in zooming; an aperture stop; and one or two rear lens units including a rear lens unit closest to the object side and configured not to move for zooming. An interval between each pair of adjacent lens units is changed in zooming. The three or four moving lens units include a moving lens unit having a negative refractive power. The three or four moving lens units include a rear positive lens unit closest to the image side and having a positive refractive power. The first lens unit includes three positive lenses. Conditional expressions are satisfied by the zoom lens.

Abstract: The present disclosure relates to the field of optical lenses and provides a camera optical lens sequentially including, from an object side to an image side, first to seventh lenses. The camera optical lens satisfies following conditions: 2.00?R1/d1?4.00; 20.00?v4?v5?30.00; 1.00?(R1+R2)/(R3+R4)?2.50; and 1.00?R12/R11?2.80, where v4 and v5 denote abbe numbers of the fourth and fifth lenses, respectively; R1 and R2 denote curvature radiuses of an object side surface and an image side surface of the first lens, respectively; R3 and R4 denote curvature radiuses of an object side surface and an image side surface of the second lens, respectively; R11 and R12 denotes curvature radiuses of an object side surface and an image side surface of the sixth lens, respectively; and dl denotes an on-axis thickness of the first lens. The camera optical lens can achieve high optical performance while satisfying design requirements for ultra-thin, wide-angle lenses having large apertures.

Abstract: An optical imaging apparatus includes a plurality of optical lenses. The optical lenses are arranged along an optical axis to capture an image in an image capture direction and project the image on an imaging plane. The plurality of optical lenses are divided into at least one fixed lens set and at least one movable lens set. The fixed lens set is fixedly disposed, and the movable lens set is configured to move relative to the fixed lens set, so as to adjust focal lengths of the optical lenses.

Abstract: A zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the first lens group and the fifth lens group are not moved, and the second lens group, the third lens group, and the fourth lens group are moved. The second lens group includes a negative lens closest to the object side. In a case where a focal length of the second lens group is denoted by f2 and a focal length of the negative lens of the second lens group closest to the object side is denoted by f21, the zoom lens satisfies 0.6<f2/f21<0.9.

Abstract: The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression related to a distance from a lens surface of the first lens group closest to the object side to an image plane and a distance from a lens surface of the second lens group closest to the object side to the image plane is satisfied.

Abstract: A zoom lens includes a first lens unit having negative refractive power, a second lens unit having positive refractive power, an intermediate unit including one or more lens units, and a final lens unit having positive refractive power disposed closest to the image side. The first lens unit includes negative lenses G1, G2 and G3 disposed in this order from an object side to an image side. The final lens unit includes at least one negative lens and a positive lens disposed closest to the image side. The zoom lens satisfies predetermined inequalities.

Abstract: A zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the first lens group and the fifth lens group are not moved, and the second lens group, the third lens group, and the fourth lens group are moved. The first lens group consists of one negative lens and five positive lenses in order from the object side to an image side. Predetermined conditional expressions related to a refractive index, an Abbe number, and a partial dispersion ratio of the negative lens of the first lens group are satisfied.

Abstract: An optical imaging lens module is provided, the optical imaging lens module may include a first lens barrel and a second lens barrel, positioned in an order from an image side to an object side along an optical axis; an optical imaging lens, comprising a first lens element group and a second lens element group, disposed in the first lens barrel and the second lens barrel respectively; an actuating unit, disposed on an external side of the second lens barrel to make the second lens barrel to be a movable barrel, which can move along the optical axis relative to the first lens barrel. The optical imaging lens may satisfy EFL/TTL?0.850, in which a system focal length is represented by EFL, and a distance from an object-side surface of the lens element having refracting power and closest to the object side to an imaging plane along the optical axis is represented by TTL.

Abstract: A variable magnification optical system includes, in order from an object: a first lens group (G1) having a negative refractive power; a second lens group (G2); a third lens group (G3); a fourth lens group (G4) having a negative refractive power; and a fifth lens group (G5) having a positive refractive power, the system performing varying magnification by changing the distance between the first and second lens groups, the distance between the second and third lens groups, the distance between the third and fourth lens groups, and the distance between the fourth and fifth lens groups, and the fourth lens group including a 42nd lens group (G42) configured to be movable so as to have a component in a direction orthogonal to an optical axis and a 41st lens group (G41) disposed at an object-side of the 42nd lens group.

Abstract: A zoom lens includes, in order from an object side, a first lens group that is positive, a second lens group that is negative, a third lens group that is positive, and a fourth lens group that is positive. During zooming from a wide angle end to a telephoto end, at least the first lens group and the third lens group are fixed and an interval on an optical axis of an adjacent lens group relative thereto is changed. In the zoom lens, the fourth lens group includes at least one positive lens and satisfies a predetermined conditional expression. In addition, an imaging device includes the zoom lens and an image sensor.

Abstract: A zoom lens includes a negative first lens group, a positive second lens group, and a subsequent lens group in order from an object side. A focusing lens group closer to an image side than the first lens group moves during focusing. The first lens group consists of a first-a lens group and a first-b lens group in order from the object side. Assuming that an average of refractive indices of the negative lenses of the first-a lens group is Nd1ave, a focal length of the focusing lens group is ff, and a focal length of the first lens group is f1, Conditional Expression (1) of 1.73<Nd1ave<1.95 and Conditional Expression (2) of 1<|ff/f1|<3 are satisfied.

Abstract: Multi-cameras and in particular dual-cameras comprising a Wide camera comprising a Wide lens and a Wide image sensor, the Wide lens having a Wide effective focal length EFLW and a folded Tele camera comprising a Tele lens with a first optical axis, a Tele image sensor and an OPFE, wherein the Tele lens includes, from an object side to an image side, a first lens element group G1, a second lens element group G2 and a third lens element group G3, wherein at least two of the lens element groups are movable relative to the image sensor along the first optical axis to bring the Tele lens to two zoom states, wherein an effective focal length (EFL) of the Tele lens is changed from EFLT,min in one zoom state to EFLT,max in the other zoom state, wherein EFLTmin>1.5×EFLW and wherein EFLTmax>1.5×EFLTmin.

Abstract: Provided is a zoom lens including, in order from an object side: a positive first unit not moving for zooming; one or two moving units move for zooming and including a negative unit; a negative unit moving for zooming; a positive unit including a stop and moving for zooming; and a positive final unit not moving for zooming. The distances on the optical axis, from surface, closest to the object side, of the first unit to a surface, closest to an image side, of the first unit, from the surface, closest to the object side, of the first unit to the stop at the wide angle end, from the surface, closest to the image side, of the first unit to the stop at the wide angle end, and the maximum distance from the surface, closest to the image side, of the first unit to the stop are appropriately set.

Abstract: Provided is a zoom lens including, from object side: one/two first positive units including a lens unit arranged at closest to object side not movable for zooming ; one/two second negative units movable toward image side for zooming from wide end to telephoto end; one/two third units including a negative unit arranged closest to object side and movable along a locus convex toward object side for zooming; a fourth positive unit movable for zooming; and a fifth unit, and including an aperture stop in image side of the fourth unit. A distance between object side surface of the first unit and the aperture stop, a length of the first unit, and movement amounts of the second unit from wide end to telephoto end and of the fourth unit from wide end to an intermediate zoom state where the second and third units are closest to each other are set appropriately.

Abstract: A zoom optical system includes, disposed in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. At least a part of the third lens group is arranged to be movable along an optical axis as a focusing lens group, and the focusing lens group is moved toward an image when a focusing state on a long-distance object is changed to a focusing state on a short-distance object. The following conditional expression is satisfied: 0.90<f3/fw<1.50, where f3 denotes a focal length of the third lens group and fw denotes a focal length of the zoom optical system in a wide-angle end state.

Abstract: An optical system includes an object side lens unit arranged closest to an object, immobilized in focusing, and having a positive refractive power, an image plane side lens unit arranged closest to an image plane and having a negative refractive power, and a first focus lens unit and a second focus lens unit which are arranged between the object side lens unit and the image plane side lens unit and are moved in focusing. The object side lens unit consists of a first partial unit having the negative refractive power, a second partial unit having the positive refractive power, a third partial unit having the positive or the negative refractive power which are arranged in order from an object side to an image plane side. The second partial unit is moved in a direction including a component in a perpendicular direction to an optical axis in image blur correction.

Abstract: A first lens group (G1) having positive refractive power, a second lens group (G2) having negative refractive power, a third lens group (G3) having positive refractive power, a fourth lens group (G4) having positive refractive power, a fifth lens group (G5) are arranged in order from an object, and a distance between the first lens group (G1) and the second lens group (G2), a distance between the second lens group (G2) and the third lens group (G3), a distance between the third lens group (G3) and the fourth lens group (G4), and a distance between the fourth lens group (G4) and the fifth lens group (G5) change upon zooming, and a lens group arranged closest to an image is approximately fixed against an image surface (I) upon zooming, and the third lens group (G3) moves along the optical axis upon focusing, and the following expression (1) is satisfied. 0.480<f3/ft<4.

Abstract: The zoom lens consists of, in order from an object side, a positive first lens group, a negative second lens group, a third lens group, a positive fourth lens group, and a positive fifth lens group. During zooming, the second lens group, the third lens group, and the fourth lens group move. The first lens group consists of, in order from an object side, a negative first a lens group, a positive first b lens group that moves during focusing, and a positive first c lens group. A most-image-side lens of the first b lens group is a negative meniscus lens having a convex surface facing an object side.