Abstract: A method of manufacturing a camera module that is low profile and that can achieve superior resolving power, a camera module, and an imaging device are provided. A positioning step of positioning an object-side group optical unit (12a) along an optical axis direction with the use of a jig (40) such that the object-side group optical unit (12a) is located so as not to be in contact with an image-plane-side group lens (32a) and a fixing step of fixing the object-side group optical unit (12a) to a lens holder (20) are included.

Abstract: An inverted equal-magnification relay lens includes, in order from an object side: a first lens group having a positive power, and disposed near an object; a second lens group having a positive power, and disposed at a predetermined distance from the first lens group; and a third lens group having a negative power; wherein an entrance pupil position is more toward an object surface side than the first lens group, an exit pupil position is more toward a third lens group side than an image surface, and the following Formulas (1) and (2) are satisfied: 0.65?|G1F/G2F|?2.0 . . . (1); 0.35?|G3F/G2F|?3.1 . . . (2); where: G1F: a focal length of the first lens group; G2F: a focal length of the second lens group; and G3F: a focal length of the third lens group.

Abstract: A system for guidance of an imaging device may include a handheld imaging device, a multidirectional feedback device, and a control unit in communication with the multidirectional feedback device and the handheld imaging device. The control unit may be configured to receive a target location, determine an initial position and pose of the handheld imaging device, calculate a position and pose deviation relative to said initial position and pose, translate said position and pose deviation into control data, and transmit said control data to the multidirectional feedback device, wherein the multidirectional feedback device uses control data to provide an operator with feedback to guide the handheld imaging device towards the target.

Abstract: The zoom lens includes: a first optical system on a magnification side; and a second optical system on a reduction side in a state where the intermediate image is formed between the magnification side and the reduction side. The first optical system includes, in order from the magnification side, a first-1 lens group which has a positive power, and a first-2 lens group which has a positive power. The second optical system includes, in order from the magnification side, a second-1 lens group which has a positive power, a second-2 lens group which has a positive power, and a second-3 lens group which has a positive power. The first-2 lens group, the second-1 lens group, and the second-2 lens group move during zooming. The first-1 lens group and the second-3 lens group remain stationary during zooming.

Abstract: An optical imaging system is described including first to sixth lenses sequentially disposed from an object side to an image side, and an image sensor configured to convert incident light reflected from a subject, having passed through the first to sixth lenses, into an electrical signal. One of the first to sixth lenses includes a spherical object-side surface and another of the first to sixth lenses includes corresponding aspherical object-side surfaces. The first to sixth lenses include corresponding aspherical image-side surfaces, and a lens of the first to sixth lenses that is closer to the object side than the one of the first to sixth lenses including the spherical object-side surface, has a highest refractive index among the first to sixth lenses.

Abstract: An optical assembly for a point action camera with a wide field of view includes multiple lens elements configured to provide a field of view in excess of 150 degrees. One or more lens elements has an aspheric surface. The optical assembly exhibits a low inward field curvature of less than 75 microns.

Abstract: The present invention relates to a solar position tracking accuracy measurement system based on an optical lens, by which the solar position tracking accuracy of a tracker can be effectively analyzed and detected in real-time by using a technique on the basis of an astronomical analysis on the trajectory of the sun through an accurate measurement based on an optical lens, thereby establishing the reproducibility of a physical measurement method, calculating an error angle according to the vertical incidence of solar light and minimizing physical errors.

Abstract: Provided is a zoom lens, including: a negative first lens unit; an aperture stop; and a positive second lens unit, in which the first and second lens units are configured to move so that an interval between the first and second lens units is changed in an optical axis direction, in which the second lens unit includes a positive lens and a negative lens, and in which, when refractive indices of a material with respect to a wavelengths of 400 nm, 1,050 nm and 1,700 nm are respectively represented by Ns, Nm and Nl, and a relative partial dispersion ? of the material is expressed as: ?=(Ns?Nm)/(Ns?Nl), an average value ?IR(G2p)AVE of relative partial dispersions of materials of the positive lens in the second lens unit, and an average value ?IR(G2n)AVE of relative partial dispersions of materials of the negative lens in the second lens unit are appropriately set.

Abstract: A zoom lens comprising in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a negative refractive power, a lens unit having a positive refractive power, and a rearmost lens unit having a negative refractive power, and the rearmost lens unit is positioned nearest to an image in the plurality of lens units, and at the time of zooming, distances between the lens units in the plurality of lens units change. Moreover, an image pickup apparatus includes the zoom lens, and an image pickup element having an image pickup surface.

Abstract: The present invention discloses a photographic optical system which includes a first lens (focal length f1), a second lens (focal length f2), a third lens (focal length f3), a fourth lens (focal length f4), a fifth lens (focal length f5), a sixth lens (focal length f6) and a seventh lens (focal length f7). The photographic optical system disclosed in the present invention by optimizing rationally face shape, distributing focal power, selecting optical material, is designed as a big relative aperture photographic optical system, and can provide the imaging performance in low illumination environment.

Abstract: An imaging lens for a solid-state imaging sensor includes, in order from an object side to an image side of the imaging lens, a first through sixth lens. The first lens has positive refractive power. The second lens has positive refractive power. The third lens has negative refractive power. The fourth lens has positive or negative refractive power and aspheric surfaces facing the object side and the image side. The fifth lens has positive refractive power. The sixth lens has negative refractive power and aspheric surfaces facing the object side and the image side.

Abstract: An inner focusing lens has sequentially from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a negative refractive power. The first lens group has negative meniscus lenses disposed farthest on the object side thereof. The second lens group is moved along the optical axis whereby focusing from a focus state for an object at infinity to a focus state for the minimum object distance is performed. The inner focusing lens satisfies predetermined conditions and thereby, realizes a compact inner focusing lens having high imaging performance at wide angles, suitable for compact cameras having a function of capturing video.

Abstract: A projection zoom lens is essentially constituted by, in order from the magnification side: a negative first lens group; a positive second lens group; a third lens group; a positive fourth lens group; a fifth lens group; and a positive sixth lens group. The distance between the first and second lens groups is shorter, the distance between the second and third lens groups is longer, the distance between the third and fourth lens groups is shorter, the distance between the fourth and the fifth lens groups is longer, and the distance between the fifth and sixth lens groups is longer at the telephoto end than at the wide angle end. A lens having a negative refractive power in the paraxial region is provided most toward the magnification side in the first lens group. The fifth lens group has a negative lens.

Abstract: An optical imaging lens includes: a first, second, third and fourth lens element, the first lens element has negative refractive power, the second lens element has an image-side surface with a concave part in a vicinity of the optical axis, the third lens element has positive refractive power, and has an object-side surface with a convex part in a vicinity of the optical axis, the fourth lens element has an image-side surface with a concave part in a vicinity of the optical axis, where the optical imaging lens set does not include any lens element with refractive power other than said first, second, third and fourth lens elements.

Abstract: A zoom lens consists of a negative first lens group, a positive second lens group, and a positive third lens group. Upon zooming from the wide angle end to the telephoto end, the first, second, and third lens groups are moved such that distance between the first lens group and the second lens group is reduced, and distance between the second lens group and the third lens group is increased. The first lens group is composed of a negative lens and a positive lens from the object side. The zoom lens satisfies given conditional expressions related to radius of curvature, center thickness, refractive index, and Abbe number of the negative lens and refractive index of the positive lens of the first lens group, and distance from the most object side surface to the most image side surface of the first lens group on the optical axis.

Abstract: An inner focusing lens has sequentially from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a negative refractive power. The first lens group has negative meniscus lenses disposed farthest on the object side thereof. The second lens group is moved along the optical axis whereby focusing from a focus state for an object at infinity to a focus state for the minimum object distance is performed. The inner focusing lens satisfies predetermined conditions and thereby, realizes a compact inner focusing lens having high imaging performance at wide angles, suitable for compact cameras having a function of capturing video.

Abstract: A zoom lens is provided which has a wide angle of view and is bright and in which the entire lens system is compact and which can achieve high optical characteristic over the entire zoom range.

Abstract: The present invention provides a camera device and an optical imaging lens thereof. The optical imaging lens comprises six lens elements positioned in an order from an object side to an image side. Through controlling the convex or concave shape of the surfaces of the lens elements, the view angle of the optical imaging lens is efficiently increased to shows better optical characteristics.

Abstract: A zoom lens including, in order from an object side: a positive first lens unit; a negative second lens unit; and a positive third lens unit, in which: an interval between the first and second lens units is increased, and an interval between the second and third lens units is decreased during zooming from a wide angle end to a telephoto end; the second lens unit is an image stabilizing lens unit which moves with a component of motion in a direction perpendicular to an optical axis whereby an imaging position is moved in the direction of motion perpendicular to the optical axis; and a focal length of an entire system at the wide angle end, a focal length of the first lens unit, and a movement amount of the first lens unit during zooming from the wide angle end to the telephoto end are each set appropriately.

Abstract: A condensing system and method with a plurality of LEDs is disclosed. The LEDs are positioned on the same plane. A first condensing lens is disposed at front of each LED, a second condensing lens is disposed at front of each first condensing lens, a third condensing lens is disposed at front of each second condensing lens, and a fourth condensing lens is disposed at front of all the third condensing lenses. After the light emitted by each LED is condensed by the corresponding first condensing lens, second condensing lens and third condensing lens, the divergence angle of the light becomes smaller, forming a bunch of nearly parallel light beams. The bunches of nearly parallel light beams simultaneously transmit through the fourth condensing lens, and then combine. The condensing system can be used as the light source with imaging lenses disposed therebehind to form an imaging system.

Abstract: A zoom lens system having a plurality of lens units, each lens unit being composed of at least one lens element, the zoom lens system, in order from an object side to an image side, comprising: a first lens unit having negative optical power and being composed of at least two lens elements; and a second lens unit having positive optical power, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the lens units are individually moved along an optical axis to vary magnification such that an interval between the first lens unit and the second lens unit decreases, and the conditions: fW/D1>7.5 and Z=fT/fW>4.0 (fW: a focal length of the entire system at a wide-angle limit, fT: a focal length of the entire system at a telephoto limit, D1: a center thickness of a lens element located on the most object side in the first lens unit) are satisfied; an imaging device; and a camera.

Abstract: This super-wide lens substantially consists of a positive first lens group, a positive second lens group, and a negative third lens group, in this order from the object side. The first lens group and the third lens group are fixed and the second lens group moves toward the object side while focusing from an object at infinity to an object at the closest distance. The first lens group substantially consists of a negative first sub lens group, a positive second sub lens group, an aperture stop, and a positive third sub lens group in this order from the object side. Conditional expressions (1) and (2) are satisfied: 0.15<f1/f2<0.60??(1) 2.5<f2/f<7.0??(2), where f1: the focal length of the first lens group, f2: the focal length of the second lens group, and f: the focal length of the entire system when focusing on an object at infinity.

Abstract: A zoom lens includes an imaging lens unit having a positive refractive power and provided nearest to an image-side end, and a focusing lens unit having a positive refractive power and provided on an object side of the imaging lens unit. A distance between the imaging lens unit and the focusing lens unit changes during zooming. The focusing lens unit moves during focusing. The imaging lens unit includes, at a position thereof nearest to an object-side end, a negative meniscus lens component that is concave on the object side thereof.

Abstract: A zoom lens system that includes a first lens group including at least one lens and having a negative refractive power, and a second lens group including at least one lens and having a positive refractive power in an order from an object side to an image side, wherein the zoom lens system is configured to perform zooming by changing a distance between the first lens group and the second lens group and satisfies: 2<|f1/fw|<2.5 and 0.60<|f1/f2|<0.85, wherein f1 indicates a synthetic focal length of the first lens group, fw indicates an overall focal length at a wide angle end, and f2 indicates a synthetic focal length of the second lens group.

Abstract: A zoom lens includes first, second, and third lens units respectively having negative, positive, and negative refractive powers in this order from an object side to an image side. The lens units move during zooming such that the spacing between adjacent lens units changes, the second and third lens units are positioned on the object side at a telephoto end when compared to a wide angle end, and the third lens unit moves during focusing. A lateral magnification of the second lens unit at the wide angle end, a lateral magnification of the second lens unit at the telephoto end, a lateral magnification of the third lens unit at the wide angle end, a lateral magnification of the third lens unit at the telephoto end, a focal length of the first lens unit, and a focal length of the second lens unit are appropriately set.

Abstract: A variable magnification optical system includes a negative first lens group, a stop, and a positive second lens group. The distance in an optical axis direction between the first and the second lens groups is reduced when magnification is changed from the wide angle end to the telephoto end. The stop is fixed with respect to an image plane when magnification is changed, and the first lens group includes a positive lens, a negative lens, a negative lens, and a positive meniscus lens with a convex surface on the object side in order from the object side. The optical system satisfies predetermined conditional expressions with respect to the average Abbe number of the positive lens and the positive meniscus lens of the first lens group at the d-line, and the focal length of the entire system at the wide angle end and the focal length of the negative lens.

Abstract: A zoom lens and a photographing apparatus including the zoom lens that includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power that are sequentially arranged from an object side; during zooming from wide to telephoto, the distance between the first and second lens groups decreases and the distance between the second and third lens groups increases; the first lens group includes a first lens having a negative refractive power and is a double-concave lens and a second lens having a positive refractive power that are sequentially arranged from the object side; and the second lens group includes a third lens having a positive refractive power, being disposed closest to the image side, and is a meniscus lens having a concave surface toward the object side.

Abstract: A zoom lens consists of, 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, and a third lens unit having negative refractive power. The first lens unit and the second lens unit move during zooming to make a distance between the first lens unit and the second lens unit larger at a telephoto end than at a wide-angle end. The third lens unit consists of, in order from the object side to the image side, a first lens subunit having positive refractive power and a second lens subunit having negative refractive power, and the second lens subunit moves toward the image side during focusing from an infinite-distance object to a near-distance object.

Abstract: A zoom lens system comprising: a first lens unit having negative optical power; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein the first to third lens units are individually moved along an optical axis to vary magnification in zooming, each lens unit includes at least one lens element that satisfies the conditions: nd?1.67, vd<59 and 0.000<PgF+0.002×vd?0.664 (nd, vd and PgF: a refractive index to the d-line, an Abbe number to the d-line and a partial dispersion ratio, of the lens element), and the condition: 0.31<Ir/?(|fG1×fG2|) (Ir=fT×tan(?T), fT and ?T: a focal length of the entire system and a half value of maximum view angle, at a telephoto limit, fG1 and fG2: a focal length of each of the first lens unit and the second lens unit) is satisfied; an imaging device; and a camera are provided.

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, an aperture stop, a third lens unit having a positive refractive power, and a rear lens group including at least one lens unit, the first lens unit is positioned closer to the object side at a telephoto end than at a wide-angle end, the third lens unit includes at least one positive lens, and a partial dispersion ratio ?gF3P of a material of one positive lens in the third lens unit, Abbe's number ?d3P, focal lengths fW and fT of a total system at the wide-angle end and the telephoto end respectively, a focal length f1 of the first lens unit, and a focal length f3 of the third lens unit are appropriately set.

Abstract: A zoom lens includes a first lens group, a second lens group and a third 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 negative refractive power and includes a first lens, a second lens and a third lens, wherein the first lens is with negative refractive power, the second lens is with positive refractive power and the third lens is with negative refractive power. The second lens group is with positive refractive power. The third lens group is with positive refractive power. The third lens satisfies |R31/R32|?0.39, wherein R31 is a radius of curvature of an object side surface of the third lens and R32 is a radius of curvature of an image side surface of the third lens.

Abstract: A zoom lens includes, in order from the object side, a negative first lens group, a positive second lens group and a positive third lens group, wherein, during magnification change from the wide-angle end to the telephoto end, at least the first and second lens groups are moved such that the interval between the first and second lens groups decreases and the interval between the second and third lens groups increases. The first lens group includes a negative meniscus first-group first lens with a convex object-side surface, a negative meniscus first-group second lens with a convex object-side surface, and a positive first-group third lens with a convex object-side surface, and the second lens group includes a positive lens, a cemented lens formed by a positive lens and a negative lens, a positive lens and a negative lens, in order from the object side. The zoom lens satisfies given conditional expressions.

Abstract: Various embodiments provide an optical system including a first lens group having a plurality of lenses; a second lens group having a plurality of lenses, the second lens group being disposed adjacent the first lens group; a third lens group having a plurality of lenses, the third lens group being disposed adjacent the second lens group; and a detector disposed behind the third lens group. A pupil of the optical system is located external to the first lens group, the second lens group and the third lens group. The second lens group is movable respective to the first lens group and the third lens group so as to convert a configuration of the optical system between a narrow field of view (NFOV) configuration and a wide field of view (WFOV) configuration.

Abstract: In a zoom lens, at least a first group of negative optical power and a second group of positive optical power are included from an object side, when zooming is performed from a wide-angle end to a telephoto end, a distance between the first and the second groups is reduced and an aperture is moved together with the second group. The first group is formed with a front group composed of only negative lenses and a rear group which is composed of two lenses, a positive and a negative from the object side and which has a positive optical power as a whole and the zoom lens satisfies a conditional formula: 0.06<T1/Lmax<0.11 (T1 is a distance on an optical axis between the front and rear groups, and Lmax is the maximum total length of the zoom lens in zooming).

Abstract: A zoom lens substantially consists of a negative first lens group, a positive second lens group, and a positive third lens group; wherein the first lens group substantially consists of a two negative lenses with concave surfaces toward the image side and a positive lens with a convex surface toward the object side; the second lens group substantially consists of a stop; a positive lens with a convex surface toward the object side; a positive cemented lens, which is formed by a positive lens with a convex surface toward the object side and a negative lens with a concave surface toward the image side together; and a negative aspherical lens with a convex surface toward the image side; and the third lens group substantially consists of a positive lens.

Abstract: A zoom lens includes, in order from an object side to an image side, a positive first lens unit, a negative second lens unit, a positive third lens unit, and a positive fourth lens unit. During zooming from a wide-angle end to a telephoto end, the first lens unit moves with a locus convex toward the image side, and the third lens unit moves toward the object side. The first lens unit includes, in order from the object side to the image side, a negative first lens, a positive second lens, and a positive third lens. A distance (d12) between the first lens and the second lens, a focal length (fw) of the entire zoom lens at the wide-angle end, and a refractive index (Np) of a positive lens having the lowest refractive index among the refractive indices of materials of all positive lenses included in the first lens unit are appropriately set based on predetermined mathematical conditions.

Abstract: A projection optical system substantially consists of a first optical system composed of a plurality of lenses and a second optical system composed of one reflection mirror having a convex aspherical surface arranged in this order from the reduction side and is configured, when an air space between the first optical system and the second optical system is taken as T12 and a displacement in a direction of the optical axial from a position of maximum effective height on the magnification side lens surface of the lens disposed on the most magnification side in the first optical system to the vertex of the lens surface is taken as Zf, to satisfy a conditional expression (1): 0.1<Zf/T12<1.0, in which an image formed on a conjugate plane on the reduction side is magnified and projected onto a conjugate plane on the magnification side.

Abstract: Provided are an ocular zoom optical system which has a wide apparent field of view even on a low power side and in which aberrations are favorably corrected while a sufficient eye relief is secured over the entire zoom range, and an optical instrument including the ocular zoom optical system. The ocular zoom optical system 3 includes, in order from the object side: a first lens group G1 having a negative refractive power; a second lens group G2 having a positive refractive power; and a third lens group G3 having a positive refractive power and at least one aspheric surface. An intermediate image I? is formed between the first lens group G1 and the second lens group G2. During zooming, the third lens group G3 is fixed on the optical axis, and the first lens group G1 and the second lens group G2 are moved in directions opposite to each other with the intermediate image I? interposed therebetween.

Abstract: A zoom lens includes, in order from the object side, a positive first unit, a zooming lens group constituted by at least two lens units having a zooming function and a function of correcting image plane variation with zooming, and a last lens unit disposed on the most image side having an imaging effect and not moving for zooming. The first unit includes a negative first sub unit not moving for focusing, a second sub unit moving during focusing, and a positive third sub unit not moving for focusing. The first sub unit is composed of one or more concave lenses, and the third sub unit is composed of one or more convex lenses. Of the first and third sub units, the refractive powers, the average Abbe constants and the paraxial converted beam heights at the telephoto end are appropriately set.

Abstract: A variable magnification optical system includes, in order from the object side, a negative first lens group and a positive second lens group, wherein the interval between these lens groups in the optical axis direction is changed during magnification change. The most image-side lens and the second most image-side lens of the first lens group are a negative single lens with a concave surface facing the object side and a positive single lens, respectively. The second lens group includes, in order from the object side, a positive lens disposed at the most object-side position with at least one surface thereof being an aspherical surface, a first cemented lens formed by a negative lens and a positive lens, and a second cemented lens formed by a negative lens and a positive lens.

Abstract: A zoom lens substantially consists of a positive first lens group, a negative second lens group which moves from the object side to the image side while changing magnification from the wide angle end to the telephoto end, a negative third lens group, and a positive fourth lens group having an aperture stop St, wherein the first lens group includes a negative meniscus lens on the most-object side; the second lens group is composed of a negative second-a lens group having at least one aspheric surface and a positive second-b lens group, and the distance therebetween changes while changing magnification; a third lens group moves such that the distance between the third lens group and a fourth lens group at the telephoto end becomes narrower than at the wide angle end; and conditional expression (1) below is satisfied: 1.89<N1a1??(1).

Abstract: A zoom lens includes: a first lens group having a positive refractive power which is fixed while changing magnification; a second lens group constituted by two or more magnification changing groups; an aperture stop; and a third lens group having a positive refractive power which is fixed while changing magnification, provided in this order from an object side. The magnification changing groups respectively move along an optical axis while changing magnification from a wide angle end to a telephoto end. The zoom lens satisfies the following conditional formula: u?/u<0.5??(1) wherein u is the angle of inclination of a paraxial chief ray of light that enters the lens surface most toward the object side within the first lens group, and u? is the angle of inclination of the paraxial chief ray of light that exits the lens surface most toward an image side within the first lens group.

Abstract: The zoom lens includes a front unit including a first positive lens unit and a second positive or negative lens unit, a reflective mirror and a rear unit including two or more lens units. During zooming, the reflective mirror is not moved, and the first lens unit and at least two lens units of the rear unit are moved. When the zoom lens is retracted into a body of an image pickup apparatus, at least one of rotation of the reflective mirror such that a normal line thereto is brought closer to parallel to an optical axis of the rear unit and axial movement thereof in a direction of the optical axis of the rear unit is performed. The front unit is moved into a space formed by the at least one of the rotation and the axial movement. Conditions of 10.5<ft/|fn|<30.0 and 0.80<(Lf?L)/Lm<1.30 are satisfied.

Abstract: A zoom lens system includes, in order from the object side to the image side, a first, a second, and a third lens groups. The first lens group includes, in order from the object side to the image side, a first and a second lenses. The second lens group is capable of floating to realize an image stabilizating function and includes, in order from the object side to the image side, a third to sixth lenses. The zoom lens system satisfies various formulas, including 0.3<d2a/D2<0.4, wherein d2a is the distance between image-side surfaces of the fifth lens and of the sixth lens, and D2 is a width of the second lens group along an optical axis of the zoom lens system.

Abstract: A zoom lens system includes a negative first lens group and a positive second lens group, in that order from the object side, wherein upon zooming from the short focal length extremity to the long focal length extremity, the first lens group and the second lens group move in the optical axis direction while the distance therebetween mutually decreases. The first lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side, wherein the second sub-lens group constitutes a focusing lens group that is moved in the optical axis direction during a focusing operation.

Abstract: A zoom lens system comprising: a negative first lens unit; a positive second lens unit; and a positive third lens unit, wherein the first to third lens units are individually moved along an optical axis to vary magnification in zooming, the first lens unit is composed of two lens elements and includes a positive lens element having at least one aspheric surface, the third lens unit is composed of one lens element, and the condition: 1.74<Ir/?{square root over ((|DL1×fG1|))} (DL1: an optical axial thickness of an object side first lens element in the first lens unit, fG1: a focal length of the first lens unit, Ir=fT×tan(?T), fT and ?T: a focal length of the entire system and a half value of maximum view angle at a telephoto limit) is satisfied; an imaging device; and a camera are provided.

Abstract: A zoom lens comprises, in order from its object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. The first lens unit comprises a first lens having a negative refractive power and a second lens having a positive refractive power. The zoom lens satisfies the following conditional expressions (1), (2), and (3): n1n?1.70??(1), n1p?1.70??(2), and |?1n??1p?31??(3), where n1n is the refractive index of the first lens having a negative refractive power in the first lens unit for the d-line, ?1n is the Abbe constant of the first lens having a negative refractive power in the first lens unit, n1p is the refractive index of the second lens having a positive refractive power in the first lens unit for the d-line, and ?1p is the Abbe constant of the second lens having a positive refractive power in the first lens unit.

Abstract: A zoom lens including a first lens group and a second lens group is provided. Refractive powers of the first lens group and the second lens group are respectively negative and positive. The first lens group includes a first lens, a second lens, and a third lens arranged in sequence from an object side to an image side. The second lens group is disposed between the first lens group and the image side, and includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence from the object side to the image side. The zoom lens satisfies ?2.4<f1/fw<?1.0, wherein f1 is the effective focal length of the first lens group, and fw is the effective focal length of the zoom lens at a wide end.

Abstract: A zoom lens includes, in order from the object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power. The first lens unit includes a negative lens and a positive lens. The zoom lens satisfies the following conditional expression (1): ?d13/ft<0.4??(1) where ?d13 is the total sum of the thickness of the lenses included in the first to third lens units of the zoom lens on the optical axis, and ft is the focal length of the entire zoom lens system at the telephoto end.

Abstract: An optical system for imaging an object on an image acquisition unit has a variable focal length for zooming. The optical system has precisely three lens units from the object in the direction of an image acquisition unit, namely a first lens unit, a second lens unit, and a third lens unit. The second lens unit and the third lens unit are movably situated along an optical axis of the optical system for a change of the focal length. The first lens unit includes a first lens group and a second lens group. The first lens group of the first lens unit is fixedly situated on the optical axis of the optical system. The second lens group of the first lens unit is movably situated along the optical axis of the optical system for focusing. The second lens group includes at least two lenses.