Abstract: A vehicle projection lens includes a plastic aspheric first lens, an aperture stop, a cemented lens consisting of a glass second lens and a glass third lens, and a glass fourth lens arranged in order from a magnified side to a minified side. An F-number of the vehicle projection lens is smaller than or equal to 0.8, and the vehicle projection lens consists essentially of four lenses respectively with positive, positive, negative and positive refractive powers.

Abstract: A high-efficiency lamp, emitting light from a front surface, and having a high-efficiency light source, producing a first light beam. An iris assembly has an annular body that defines a first annulus and has iris blades which can be extended into the annulus to form a second, smaller, annulus. This iris assembly is positioned relative to the light source so that the iris blades are in front of the high-efficiency light source. The annular body and therefore the first annulus have finite depth from back to front. A light guide is placed immediately behind the iris blades and defines a channel that is open at its back and its front and has a reflective interior surface, with the open back being transversely coincident to the light source so that light from the light source can travel through the channel to and out from the open front.

Abstract: A lens module includes a first lens having positive refractive power, a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, a fifth lens having positive or negative refractive power, and a sixth lens having negative refractive power. One or more inflection points may be formed on an image-side surface of the sixth lens.

Abstract: A camera system including a first imaging sensor having a first imaging surface with a first diagonal length, a first lens arranged to guide a first image formation light flux toward the first imaging surface with the first image formation light flux having at the first imaging surface a width equal to or greater than the first diagonal length, a second imaging sensor having a second imaging surface with a second diagonal length, a second lens arranged to guide a second image formation light flux toward the second imaging surface with the second image formation light flux having at the second imaging surface a width equal to or greater than the second diagonal length. The first lens and the second lens are oriented in opposing directions, and the first imaging sensor, the first lens, the second imaging sensor, and the second lens are each mounted partially within an enclosure.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens having negative refractive power; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape near an optical axis thereof. The third lens is formed in a meniscus shape so that a surface thereof directing to the object side is convex near an optical axis thereof. The sixth lens is formed in a meniscus shape near an optical axis thereof.

Abstract: An optical imaging lens assembly is provided. The optical imaging lens assembly includes, sequentially along an optical axis from an object side to an image side, a first lens, a second lens, a third lens, and a fourth lens. The first lens has a negative refractive power. The third lens has a positive refractive power. At least one of the second lens or the fourth lens has a positive refractive power. A center thickness CT2 of the second lens on the optical axis and a center thickness CT4 of the fourth lens on the optical axis satisfy: CT2/CT4<0.5.

Abstract: The present disclosure provides a camera lens assembly. The camera lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from an object side to an image side along an optical axis. The first lens, the second lens and the fifth lens have positive refractive powers, and the third lens and the sixth lens have negative refractive powers. A total effective focal length f of the camera lens assembly and an entrance pupil diameter EPD of the camera lens assembly satisfy: f/EPD?1.7.

Abstract: A high-efficiency medical headlamp, emitting light from a front surface, and having a high-efficiency light source, producing a first light beam. An iris assembly has an annular body that defines a first annulus and has iris blades which can be extended into the annulus to form a second, smaller, annulus. This iris assembly is positioned relative to the light source so that the iris blades are in front of the high-efficiency light source. The annular body and therefore the first annulus have finite depth from back to front. A light guide is placed immediately behind the iris blades and defines a channel that is open at its back and its front and has a reflective interior surface, with the open back being transversely coincident to the light source so that light from the light source can travel through the channel to and out from the open front.

Abstract: A head-mounted display device is provided, including an at least partially see-through display, an electrical device, and a flexible printed circuit board (FPC) arranged on a surface of a see-through portion of the display. The FPC may include a plurality of electrical traces electrically coupled to the electrical device. Each electrical trace may be separated from at least one other electrical trace by one or more respective see-through gaps. The FPC may further include a transparent material arranged between the electrical traces in each see-through gap.

Abstract: Disclosed is a lighting device (1) for generating a dynamically adjustable spotlight without moving parts. The lighting device comprises a planar array of individually addressable sets of light sources (11), each set comprising at least one light source, each of said light sources being arranged to produce a luminous distribution; a controller (20) arranged to individually address said sets of light sources; and an optical system (100) comprising a plurality of refractive lenses (110, 120, 130) common to the individually addressable light sources and arranged to shape the luminous distribution of each set of light sources into a spotlight (13) and project said spotlight in an angular direction that is a function of a position of said set in the array.

Abstract: There is provided a projection optical system capable of projecting an image formed on an image forming unit on a projection plane, which has an extremely short projection distance and a small size.

Abstract: An optical imaging system includes a first lens having a positive refractive power, a second lens having a positive refractive power, a third lens having a positive refractive power, a fourth lens having a negative refractive power, a fifth lens having a positive refractive power, wherein an object-side surface of the fifth lens is concave; and a sixth lens having a negative refractive power, wherein the sixth lens has an inflection point formed on an image-side surface thereof, wherein the first to sixth lenses are sequentially disposed from an object side toward an imaging plane.

Abstract: An ultra-wide-angle large-aperture anamorphic lens includes a cylindrical lens group and a spherical lens group arranged in sequence from the object side to the image side. The cylindrical lens group includes a first lens, a second lens, the third lens and the fourth lens. The first lens and the second lens are negative refractive power cylindrical lenses, and the third lens and the fourth lens are positive refractive power cylindrical lenses. The spherical lens group includes a fifth lens, a sixth lens, . . . , a thirteenth lens that are sequentially arranged along the direction that the optical path points to the image side. A 2.4:1 widescreen video or photo may be obtained; at the same time, because the anamorphic lens is a front anamorphic design, in addition to the anamorphic function, it will also have optical characteristics such as elliptical out-of-focus flare and sci-fi line flare.

Abstract: An optical imaging system for pickup, sequentially arranged from an object side to an image side, comprising: the first lens element with positive refractive power having a convex object-side surface, the second lens element with refractive power, the third lens element with refractive power, the fourth lens element with refractive power, the fifth lens element with refractive power; the sixth lens element made of plastic, the sixth lens with refractive power having a concave image-side surface with both being aspheric, and the image-side surface having at least one inflection point.

Abstract: A theatre light projector including a housing, a plurality of light sources, a first aperture device and a lens system. The lens system may include a first lens sector and a second lens sector, each of which may have a positive spherical optical power. The first lens sector may have a first radii, and the second lens sector may have a second radii, wherein the first radii and the second radii are substantially parallel to each other. The first aperture device may be comprised of a first aperture comprised of a color filter and/or a pattern. The plurality of light sources may be comprised of a first light source and a second light source and each may be comprised of a white solid state light source, which may be a light emitting diode. The white solid state light source may be a laser diode.

Abstract: An imaging optical system includes, in order from an enlargement conjugate side to a reduction conjugate side, a first mirror as a convex mirror, a first lens unit, a second mirror as a concave mirror, a third mirror as a concave mirror, and a second lens unit. The imaging optical system is configured to form a first intermediate real image and a second intermediate real image located at a position different from that of the first intermediate real image between the first mirror and a reduction side conjugate plane.

Abstract: A single-focus optical system includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power. The first lens unit includes either a first sub unit, a second sub unit, and a third sub unit, or one positive lens component in addition to the first sub unit, the second sub unit, and the third sub unit. The first sub-unit includes one negative lens component or a plurality of negative lens components, the second sub-unit includes two meniscus lens components, and the third sub-unit includes a plurality of positive lens components. The third lens unit includes a front side sub-unit and a rear side sub-unit. The front side sub-unit includes only a positive lens component.

Abstract: An image reading apparatus includes a reader, a transmitter, an opposing part that is placed opposite to the transmitter, and a hardware processor that controls a position of the opposing part such that a gap between the transmitter and the opposing part becomes a first gap when images are read by the reader, and a gap between the transmitter and the opposing part becomes a second gap, which is wider than the first gap, when no image is read by the reader.

Abstract: A projection lens unit (15) of a projector (10) is disposed in a state in which an optical axis (CL) of the projection lens unit deviates from a center of an image forming panel (14); a first lens holder (43) of a lens barrel (40) includes holding pieces (55a, 55b) that are provided at intervals in a circumferential direction of a first lens group (L1) and are engaged with a first portion (A1) of the first lens group positioned on a side to which the image forming panel is shifted, and a holding piece (55c) that is engaged with a second portion (A2) of the first lens group positioned on a side opposite to the side to which the image forming panel is shifted; and the linear expansion coefficient of each of the holding pieces is lower than the linear expansion coefficient of the holding piece.

Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. 0.52>F/H>0.46, where F is an effective focal length, and H is an image height.

Abstract: A projection lens unit (15) of a projector (10) is disposed in a state in which an optical axis (CL) of the projection lens unit deviates from a center of an image forming panel (14); a first lens holder (43) of a lens barrel (40) includes holding pieces (55a, 55b) that are provided at intervals in a circumferential direction of a first lens group (L1) and are engaged with a first portion (A1) of the first lens group positioned on a side to which the image forming panel is shifted, and a holding piece (55c) that is engaged with a second portion (A2) of the first lens group positioned on a side opposite to the side to which the image forming panel is shifted; and the linear expansion coefficient of each of the holding pieces is lower than the linear expansion coefficient of the holding piece.

Abstract: A projection optical system is constituted by, in order from the reduction side, a first optical system constituted by a plurality of lenses for forming an image displayed by image display elements as an intermediate image, and a second optical system constituted by a plurality of lenses for forming the intermediate image on a magnification side conjugate plane. Conditional Formula (1) below is satisfied. 1.50<f2/|f|<2.80??(1).

Abstract: Provided is a photographing apparatus having both a phase difference auto-focusing function and a contrast auto-focusing function. Provided is an auxiliary light projector capable of projecting auxiliary light of a pattern suitable for the photographing apparatus. An auxiliary light projector and a photographing apparatus including the auxiliary light projector according to an embodiment of the present disclosure may reduce an auto-focusing time with respect to an object and improve reliability of an auto-focusing function.

Abstract: A projection optical system (10) projects from a first image plane (5) on a reducing side to a second image plane (6) on an enlargement side. The projection optical system (10) includes a first optical system (11) that includes a plurality of lenses and forms a first intermediate image (51) formed inside the first optical system (11) by light incident from the reducing side into a second intermediate image (52) on the enlargement side of the first optical system (11); a second optical system (12) that includes a first reflective surface (M1) with positive refractive power which is positioned further to the enlargement side than the second intermediate image (52); and a glass block (30) that is disposed between the first optical system (11) and the first reflective surface (M1), the glass block (30) passing light rays from the first optical system (11) to the second intermediate image (52).

Abstract: Provided is a vehicular headlamp including an excitation light source, a phosphor excited by the excitation light source, a projection lens, and a scanning mechanism configured to receive light generated by an excitation light source array on a reflective surface of a reflector and scan the light toward the phosphor. The excitation light source is formed as the excitation light source array having a plurality of light emitting portions. Between the excitation light source array and the scanning mechanism, a lens array having a plurality of light condensing portions is provided. The plurality of light condensing portions are arranged to respectively face the plurality of light emitting portions, and configured to condense lights emitted from respective light emitting portions on the reflective surface, respectively, and arrange respective optical images of reflected lights on the phosphor.

Abstract: In a vehicle-mounted image recognition apparatus, a resolution of an image projected on an imaging plane of an image sensor is different at a position away from a center between a circumferential direction and a radial direction. To make a circumferential resolution higher than a radial resolution, at least a lower half of the imaging plane is located closer to a circumferential focus than a middle of a radial focus and the circumferential focus at a position off the optical axis center of the image projected on the image sensor through the image-forming optical system. This is achieved by adjusting the position of the imaging plane when manufacturing or by selecting a lens with high circumferential resolution. This apparatus improves recognition accuracy in recognizing traffic lanes without using an expensive lens exhibiting high resolution both in the circumferential direction and in the radial direction.

Abstract: A headlight of the type worn by medical and dental professionals includes a housing having an opening therein. A light source is positioned in the housing to output light through the opening. A singlet lens is mounted in the housing proximate the opening, and a doublet lens is disposed between the light source and the singlet lens.

Abstract: The present disclosure provides a projection image correcting method and a projection apparatus. The method includes: receiving real-time brightness values of M sub-images in a current to-be-displayed image, the real-time brightness values being acquired by a plurality of sensors arranged on a reflector which is located opposite to a projection lens, and obtaining a brightness adjusting value of a j-th sub-image in the current to-be-displayed image according to the real-time brightness values of the M sub-images. Adjustment is made, in combination with brightness adjusting values obtained from the current image to be displayed, to brightness values of each sub-image in an image to be displayed after the current to-be-displayed image, thereby making brightness of displayed images uniform, and improving the projection image quality.

Abstract: A projection lens has lens holding frames that hold lenses. In a case where an image forming panel is disposed to be shifted with respect to an optical axis of the projection lens, an increase in temperature of a first part on a side to which the image forming panel is shifted with respect to the optical axis L, is greater than that of a second part on the opposite side. A hollow structure, which makes the first part 36f and the second part 36g communicate with each other, has a porous layer and is filled with a heat storage medium. By circulating the heat storage medium through the inside of the hollow structure, the first part is cooled, and the second part is heated. Therefore, temperature distribution in the circumferential direction of the lens barrel becomes uniform, and deterioration in performance of the projected image is suppressed.

Abstract: A projection optical system includes a first lens unit that moves in a direction of an optical axis in adjusting an amount of field curvature and a second lens unit located closer to a reduction side than the first lens unit. The first lens unit includes an aspherical lens satisfying predetermined conditional equations.

Abstract: An exposure apparatus exposes a substrate with illumination light via a liquid. A liquid immersion member of the exposure apparatus has a lower surface, a plurality of collection ports, and a plurality of supply ports. The lower surface has an opening through which illumination light passes. The collection ports are arranged at the lower surface to surround the opening, and the supply ports are arranged at the lower surface and between the opening and the collection ports to surround the opening, such that the liquid is supplied via the supply ports onto the substrate while the substrate is arranged opposite to a plane-convex lens of a projection optical system and such that the liquid is collected via the collection ports from the substrate.

Abstract: A lithography projection objective for imaging a pattern in an object plane onto a substrate in an image plane. The projection objective comprises a multiplicity of optical elements along an optical axis. The optical elements comprise a first group of optical elements following the object plane, and a last optical element, following the first group and next to the image plane. The projection objective is tunable or tuned with respect to aberrations for the case that the volume between the last optical element and the image plane is filled by an immersion medium with a refractive index substantially greater than 1. The position of the last optical element is adjustable in the direction of the optical axis. A positioning device is provided that positions at least the last optical element during immersion operation such that aberrations induced by disturbance are at least partially compensated.

Abstract: An optical lens assembly includes a first lens element, a second lens element, a third lens element, and a fourth lens element from an object side to an image side in order along an optical axis. The first lens element to the fourth lens element each include an object-side surface facing the object side and allowing imaging rays to pass through and an image-side surface facing the image side and allowing the imaging rays to pass through. The object-side surface of the first lens element has a convex portion in a vicinity of the optical axis. The second lens element has positive refracting power, and the object-side surface of the second lens element has a concave portion in a vicinity of a periphery of the second lens element. The third lens element is made of glass having an Abbe number greater than 60.

Abstract: A color gamut controlling device and a display device including the color gamut controlling device. The color gamut controlling device includes a light sensing unit, a first calculation unit, a second calculation unit, and a color gamut calculation unit. The light sensing unit measures a luminance of external light. The first calculation unit calculates adjusted tristimulus values for each of three primary colors based on the measured luminance. The second calculation unit calculates final tristimulus values for each of the three primary colors using the adjusted tristimulus values and target tristimulus values for each of the three primary colors. The color gamut calculation unit calculates a corrected color gamut from the final tristimulus values. The light sensing unit may further measure tristimulus values of the external light for each of the three primary colors.

Abstract: In a vehicle-mounted image recognition apparatus, a resolution of an image projected on an imaging plane of an image sensor is different at a position away from a center between a circumferential direction and a radial direction. To make a circumferential resolution higher than a radial resolution, at least a lower half of the imaging plane is located closer to a circumferential focus than a middle of a radial focus and the circumferential focus at a position off the optical axis center of the image projected on the image sensor through the image-forming optical system. This is achieved by adjusting the position of the imaging plane when manufacturing or by selecting a lens with high circumferential resolution. This apparatus improves recognition accuracy in recognizing traffic lanes without using an expensive lens exhibiting high resolution both in the circumferential direction and in the radial direction.

Abstract: A projection zoom lens is constituted essentially by: a plurality of lens groups that include at least two lens groups that move when changing magnification; the distances among all pairs of adjacent lens groups changing when changing magnification; the reduction side being configured to be telecentric; and a negative first lens group, which is fixed when changing magnification, being provided most toward the magnification side. The first lens group is constituted essentially by, in order from the magnification side to the reduction side, a negative first lens, which is a meniscus lens having a convex surface toward the magnification side, a biconcave second lens, and a positive or negative third lens. Conditional Formula (1) related to fw, which is the focal length of the entire projection zoom lens at the wide angle end, and f3, which is the focal length of the third lens, is satisfied: ?0.070<fw/f3<0.070??(1).

Abstract: An imaging lens is constituted by, in order from the object side to the image side: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a stop; and a third lens group having a positive refractive power or a negative refractive power. The first lens group has at least two positive lenses, a first positive lens from among the at least two positive lenses being positioned most toward the object side, and three negative lenses being consecutively provided adjacent to the first positive lens at the image side thereof. The first lens group is fixed with respect to an imaging surface, and focusing operations are performed by moving the second lens group and the third lens group.

Abstract: A wide-angle projection lens includes a first lens group with negative refractive power, a second lens group with positive refractive power and a third lens group with positive refractive power, all of which are arranged in order from a projection side to an image source side along an optical axis. The third lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in order from the projection side to the image source side along the optical axis, wherein the third lens and the fourth lens are cemented together to form a cemented lens and there is no air gap between the third lens and the fourth lens.

Abstract: Since a relay optical system includes double gauss lenses and pairs of meniscus lenses disposed so as to be convex toward the double gauss lenses, it is possible to sufficiently minimize the occurrence of aberration from dimming light valves to color modulation light valves, to maintain an image formation state with high performance, and further to form a favorable image.

Abstract: A projection zoom lens constituted by: a negative first lens group; a positive final lens group; and moving lens groups between the first and the final lens groups that move independently while changing magnification, satisfies the conditional formulae below: 1.00<(Rf2?Rr2)/(Rf2+Rr2)??(1) 0.00?(Rr2?Rf3)/(Rr2+Rf3)<0.15??(2) 2.5<Bf/Im???(9) wherein Rf2 and Rr2 respectively are the radii of curvature of the front and rear surfaces of the second lens from the magnification side within the most reduction side moving lens group, Rf3 is the radius of curvature of the front surface of the third lens from the magnification side within the most reduction side moving lens group, Bf is the back focus of the entire system at the reduction side at the wide angle end as an air converted length, and Im? is the maximum effective image circle diameter at the reduction side.

Abstract: An imaging lens which uses a larger number of constituent lenses for higher performance and features compactness and a wide field of view. The imaging lens is composed of seven lenses to form an image of an object on a solid-state image sensor. The constituent lenses are arranged in the following order from an object side to an image side: a first lens with positive refractive power; a second lens with positive or negative refractive power; a third lens with negative refractive power; a fourth lens with positive or negative refractive power as a double-sided aspheric lens; a meniscus fifth lens having a convex surface on the image side; a sixth lens with positive or negative refractive power as a double-sided aspheric lens; and a seventh lens with negative refractive power, in which an air gap is provided between lenses.

Abstract: A photographic lens optical system includes: a first lens having a positive refractive power and a meniscus shape convex toward an object side; a second lens having a negative refractive power and a meniscus shape convex toward the object side; a doublet lens having a positive refractive power and formed by combining a third lens and a fourth lens; a fifth lens having a positive refractive power and a double convex shape; and a sixth lens having a positive refractive power and a double convex shape. The first to sixth lenses are sequentially arranged in a direction from the object side to an image side, and the photographic lens optical system satisfies the following condition: 1.5<Nd2<1.7 where Nd2 denotes a refractive index of the second lens.

Abstract: A projector includes a light source device, a diffraction element that converts light from the light source device into 0-th order light and diffracted light, a light modulation device that modulates the diffracted light so as to form image light, and a projection optical system that emits projected light having a chief ray which is tilted with respect to an optical axis of the image light incident from the light modulation device. Defining a reference plane as a plane which is perpendicular to a plane including the optical axis and a chief ray of the projected light and includes the optical axis, a plane including an optical axis of the 0-th order light and a chief ray of the diffracted light intersects the reference plane.

Abstract: The imaging lens substantially consists of a first lens group having a positive refractive power and a second lens group having a positive refractive power, in which the entire second lens group moves along the optical axis to perform focusing. In the imaging lens, the first lens group comprises a positive first lens, a negative second lens, a negative third lens, a positive fourth lens, and a positive fifth lens in this order from the object side. When the Abbe number of the second lens with respect to the d-line is ?d2 and the Abbe number of the third lens with respect to the d-line is ?d3, conditional formula (1) below is satisfied: 2.0<?d2/?d3??(1).

Abstract: A wide angle lens consists of a negative first lens group, a positive second lens group, a stop, and a positive third lens group in order from the object side. The first lens group includes two negative meniscus lenses, each with a convex surface on the object side. The second lens group includes one pair of cemented lenses. The third lens group includes two pairs of cemented lenses and at least one aspherical surface.

Abstract: In a projection optical system that projects an image displayed on an image display device arranged on a reduction-side conjugate plane onto a magnification-side conjugate plane, as a magnified image, the projection optical system includes a refractive optical system and a reflective optical system having negative refractive power in this order from a reduction side. Further, the following conditional formula (1) is satisfied: L/D+2?min/?max?1.01??(1).

Abstract: In a projection optical system that projects an image displayed on an image display device arranged on a reduction-side conjugate plane onto a magnification-side conjugate plane, as a magnified image, the projection optical system includes a refractive optical system and a reflective optical system having negative refractive power in this order from a reduction side. Further, the following conditional formula (1) is satisfied: ?0.0015?(1/tan(?max)?0.16)×(?L/?M?0.27) ??(1).

Abstract: An imaging optical system includes a front lens group including a front lens element and a reflector element which reflects a light bundle that exits from the front lens element; and a rear lens group on the image side of the front lens group. The front lens element is a spherically-swingable lens group which suppresses image shake by spherically-swinging about a predetermined spherical-swing center in accordance with vibrations applied to the imaging optical system. The following conditions (1) and (2) are satisfied: ?d>58??(1), and f/y>3??(2), wherein ?d designates the Abbe number with respect to the d-line of at least one lens element of the spherically-swingable lens group, f designates the focal length of the imaging optical system, in a state where the focal length is at a maximum, and y designates the maximum image height of the imaging plane.

Abstract: A projection zoom lens in which a magnification change operation is performed by moving three to four lens groups as moving groups, wherein a first lens group, which is a lens group on the most-magnification side, substantially consists of a moving group having a negative refractive power; a lens group on the most-reduction side is composed of a moving group having a positive refractive power; and the first lens group which is the lens group the most-magnification side substantially consists of two lenses. In this case, conditional formula (1) below is satisfied, where fw is the focal length of the entire system at the wide angle end and fm is the focal length of the lens group on the most-magnification side: ?3.5<fm/fw<?1.0??(1). This achieves miniaturization and cost reduction, and corrects various aberrations satisfactorily.

Abstract: A projection optical system, in order from a magnification side to a demagnification side, comprising a negative first lens unit, a positive second lens unit, a positive third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit, wherein the second and third lens units move along an optical axis in zooming, the first lens unit moves along the optical axis in focusing, and the conditions: ?0.55<fW/f1<?0.30 and 1.9<f123T/f123W<fT/fW (f1: focal length of first lens unit, f123W: composite focal length of first, second and third lens units at wide-angle limit, f123T: composite focal length of first, second and third lens units at telephoto limit, fW: focal length of entire system at wide-angle limit, fT: focal length of entire system at telephoto limit) are satisfied.