Abstract: An optical system includes, in order from an object side, 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. The second lens group is moved upon carrying out focusing from an infinitely distant object to a close object, at least a portion of the third lens group is moved in a direction including a component perpendicular to an optical axis, and given conditional expressions is satisfied. Accordingly, an optical system excellently suppressing variations in aberrations generated upon vibration reduction, an optical apparatus equipped therewith, and a method for manufacturing the optical system are provided.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, and a positive rearward-remaining lens group. Upon zooming from the short to long focal length extremities, the distance between the first and second lens groups increases, the distance between the second and rearward-remaining lens groups decreases, and at least the first lens group and at least part of the rearward-remaining lens group moves. The second lens group includes a negative first sub-lens group which does not move during a focusing operation, and a negative second sub-lens group which moves in the optical axis direction during a focusing operation. The positive rearward-remaining lens group includes at least two lens groups, the distance therebetween mutually changing during zooming from the short focal length extremity to the long focal length extremity.

Abstract: Disclosed herein is a subminiature optical system including: 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, wherein the second lens group is configured of a plurality of lenses of which facing surfaces are bonded to each other and the following Conditional Equation is satisfied: n1, n3>1.7??[Conditional Equation].

Abstract: A high-aperture immersion objective, in particular for confocal applications in fluorescence microscopy and for TIRF applications, having three subsystems of lenses and/or lens groups. The design of the subsystems has made it possible for a relatively large object field of 0.25 mm to be present in the case of a high-resolution numerical aperture of 1.49. Furthermore, improved transparency is possible up to a wavelength of 340 nm.

Abstract: A retrofocus-type wide angle lens includes a first lens group having negative refractive power as a whole, a second lens group having positive refractive power as a whole, a stop, and a third lens group having positive refractive power as a whole, which are arranged in this order from the object side of the retrofocus-type wide angle lens. Further, the first lens group includes two negative meniscus lenses, each having a convex surface facing the object side. Further, each of the second lens group and the third lens group includes a three-element cemented lens.

Abstract: A zoom lens includes, 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; and a third lens group that has a positive refractive power, wherein the second lens group is constituted by three lenses of a first negative lens, a second negative lens, and a positive lens which are arranged in order from the object side to the image side, wherein an aspheric surface is formed on at least an object side of the positive lens in a shape of which a curvature gradually decreases as an outer periphery of the lens gets closer from an optical axis, and wherein the following Conditional Expressions (1) and (2) are satisfied: 0.8<10×(R22r?R23f)/(R22r+R23f)<1.8??(1) 3.0<100×{D(2,23)/TH2}<7.0??(2).

Abstract: Embodiments of an optical zoom lens system may comprise three lens groups with a PNP power sequence. The first lens group may vary focus. The second and third lens groups may be movable to vary magnification during zoom. The first lens group may include three lens subgroups with an NNP power sequence: a stationary first lens subgroup, a second lens subgroup including a movable lens element, and a stationary or movable third lens subgroup. The second lens subgroup may include two parts, which may be movable at different rates of travel to vary focus. One part may include the movable lens element. Lens elements of the first lens group may be movable according to different focus movement plans. In the first lens group, lens element movement and lens element power may contribute to provide low focus breathing over the entire zoom range. The F-number may be F/2.8 or less.

Abstract: An optical system includes, in order from an object side, 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. The second lens group is moved upon carrying out focusing from an infinitely distant object to a close object, at least a portion of the third lens group is moved in a direction including a component perpendicular to an optical axis, and given conditional expressions is satisfied. Accordingly, an optical system excellently suppressing variations in aberrations generated upon vibration reduction, an optical apparatus equipped therewith, and a method for manufacturing the optical system are provided.

Abstract: Provided is an imaging lens, including, in order from an object side: a positive first lens; a second lens having a concave shape toward the object side; and (i?2) number of lens, wherein the i-th lens, which is the most image-side lens, includes: an i-th lens flat plate; and a positive or negative lens element on at least one of the opposite surfaces of the i-th lens flat plate, wherein the following conditional relationship is satisfied: 0.9>Ymax/Y>0.61, where: Ymax is a height of the most off-axial ray on an image-side surface of the (i?1)th lens; and Y is a maximum image height.

Abstract: An immersion type microscope objective lens OL includes, in order from a cover plate C side, a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. The first lens group G1 includes at least one cemented lens. The second lens group G2 includes at least two achromatic lenses. The third lens group G3 includes, in order from the object side, an achromatic lens CL31 having a strong concave surface facing an image side, and an achromatic lens CL32 having a strong concave surface facing the object side.

Abstract: A lens system with a first group having a positive meniscus lens and a sensor. The optical distance between the front surface of the first group and the sensor can be not greater than the height of the sensor times the image F-number, which may alternatively be referred to as the working F-number. A second group can be disposed adjacent to the front focal point of the first group, and a lens-stop can be disposed adjacent to the second group. A third group can be disposed midway between the lens-stop and the object field of the first and second groups. The image F-number can be 2.8 or greater. The first group can have a doublet formed by a first lens that is plano convex and a second lens that is plano concave. The second group can have a first, plano convex lens and a second, biconvex lens forming a doublet with a third, plano concave lens.

Abstract: A zoom lens, in order from an object side, includes a first lens group having a negative refracting power, a second lens group having a positive refracting power and an aperture stop. When zooming from a wide-angle end to a telephoto end, at least the first lens group and the second lens group move, so that an interval between the first lens group and the second lens group can become small and an interval between the second lens group and an image plane can become large. The second lens group has at least three positive lenses and two negative lenses and at least one of the three positive lenses is an aspheric positive lens and an Abbe's number of the glass type: ?d and an anomalous dispersion of the glass type: ??g,F satisfy conditions: ?d>80.0??(1) ??g,F>0.025??(2).

Abstract: The invention relates to a zoom lens favorable for offering a tradeoff between slimming down a lens system upon received in an associated lens mount and making sure a small F-number. There is a zoom lens provided, which comprises, in order from its object side, a first lens group G1 having negative refracting power, a second lens group G2 having positive refracting power, and a third lens group G3 having positive refracting power. Upon zooming from a wide-angle end to a telephoto end, the first second and third lens groups G1, G2 and G3 each move along an optical axis while a spacing between the first lens group and the second lens group becomes narrow and a spacing between the second lens group and the third lens group becomes wide. The first lens group G1 comprises one single lens that is a double-concave negative lens or two lenses: a double-concave negative lens and a positive lens. The second lens group G2 comprises two positive lenses and one negative lens.

Abstract: The purpose is to provide a large-aperture-ratio internal focusing telephoto lens applicable to a wider photographing area by equipping a vibration reduction function capable to satisfactorily correct a camera shake and the like with securing superb optical performance. The large-aperture-ratio internal focusing telephoto lens includes, 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 third lens group G3 having positive refractive power. The second lens group G2 is moved along an optical axis upon changing focus from infinity to a close-range object. The first lens group G1 has at least two cemented lenses and satisfies a given conditional expression. Either one of the cemented lens satisfies a given conditional expression.

Abstract: A zoom lens formed in a small size adaptable to a thin and portable device, having three lens groups, including, from the object plane to the image forming plane: a first lens group with a negative power, a second lens group with a positive power and a third lens group with a positive power. By controlling the ratio of the focal length of the second lens group and the focal length of the tele-photo end, image distortion may be controlled, and the total length of the lens may be reduced to shrink the size of the lens. Hence production costs may be reduced, which is important to mass production.

Abstract: A compact and light-weighted projection lens system that is capable of projecting an image at an angle as wide as 75 degrees with sufficient field angle and brightness as represented by F number of approximately 2.4, that is capable of effectively correcting chroic aberration of magnification and aberration of distortion and exhibiting optical stability against environmental variations, and that is suitable for obtaining an extraordinarily fine image by the magnification and projection.

Abstract: The present invention provides a compact, thin zoom lens. The zoom lens according to the present invention includes, from an object side to an image plane side, a first lens group having an overall negative overall refractive power, a second lens group having an overall positive refractive power; and a third lens group having an overall positive refractive power. The first lens group includes a first lens and a second lens bonded together and having a negative refractive power. The second lens group includes a third lens with a positive refractive power, and a fourth lens and a fifth lens bonded together and having a negative refractive power. The third lens group includes a sixth lens having a positive refractive power. As a result, the total length is reduced, the retracted length can be reduced, and the zoom lens can be compact and thin.

Abstract: An f&thgr; lens comprises, successively from the luminous flux entrance side, a first lens made of a negative lens having a flat surface on one side, a positive second lens having a surface with a stronger curvature directed onto the image side, and a third lens made of a negative meniscus lens cemented to the second lens; and satisfies the following conditional expressions (1) to (3): −2.2<f1/f<−1.7  (1) 0.35<f2/f  (2) 2.21<N3+0.0176&ngr;3<2.27  (3) where f is the composite focal length of the whole lens system, f1 is the focal length of first lens, f2 is the focal length of second lens, N3 is the refractive index of third lens at d-line, and &ngr;3 is the Abbe number of third lens at d-line.

Abstract: A retrofocus lens system has a negative first, a positive second and a positive third lens group. The first lens group includes an aspheric first lens, a negative meniscus second and third lenses that are convex on the large conjugate side, and a negative meniscus fourth lens being convex on the small conjugate side. The second lens group includes a positive fifth lens and a sixth lens joined to the fifth lens. The third lens group includes a positive meniscus seventh lens being convex on the small conjugate side, a biconcave eighth lens, a positive ninth lens joined to the eighth lens, a biconvex tenth and eleventh lenses, and an aspheric twelfth lens. The system satisfies 0.8<f2/f3<1.5, 1.6<|f1|/f<2.

Abstract: A wide-angle eyepiece lens having an angle of view greater than 60.degree. comprises, in order from the object end, a first lens group including a positive power meniscus lens element with a concave object side surface, an overall negative power second lens group including a doublet comprising, in order from the object side, a negative power lens element and a positive power lens element, and an overall positive power third lens group, and satisfies the following conditions:1.2<f1/f<3.53<-f2/f0.010<1/.upsilon.2N-1/.upsilon.2P1<.vertline.R3/f.vertline.wheref is the overall focal length of the eyepiece lens;f1 is the overall focal length of the first lens group;f2 is the overall focal length of the second lens group;.upsilon.2N is the Abbe number of the negative power lens element of the second lens group;.upsilon.2P is the Abbe number of the positive lens element of the second lens group;R3 is the curvature of radius of the foremost object side surface of the second lens group.

Abstract: An eyepiece system which is configured for observing an image formed by an objective lens system and comprises, in order from a side, of the objective lens system, a first lens element having at least one aspherical surface and a concave surface on the side of the objective lens system, at least one biconcave lens element and at least one positive lens element.

Abstract: A standard lens system composed, in order from the object side, of a first lens unit having a positive refractive power, an aperture stop, a second lens unit having a positive refractive power and a third lens unit having a negative refractive power: the first lens unit being composed of at least one positive meniscus lens component which has a convex surface on the object side, and at least one doublet which consists of a positive meniscus lens component and a negative lens component; the second lens unit being composed of at least one cemented doublet which consists of a negative lens element and a positive lens element, and a positive lens component; and the third lens unit being composed of at least one positive lens component and a negative lens component or at least one negative lens component.

Abstract: A lens system particularly suitable for use in a camera using small format film has two lens units, a front negative power lens unit and a rear positive power lens unit. The rear lens unit has no negative lens elements and includes an aspheric surface and a diffractive surface.

Abstract: An objective lens for an endoscope includes a first lens group having one negative lens, a second lens group having at least one positive lens, and a third lens group including a positive lens. The objective lens satisfies the following relationship:.theta..sub.g,d <-2.223.times.10.sup.-3 .cndot..nu..sub.d +1.365wherein .theta..sub.g,d =(n.sub.g -n.sub.d)/(n.sub.F -n.sub.C), n.sub.g represents the refractive index of the glass material of the first lens group at the g-line, n.sub.d represents the refractive index of the glass material of the first lens group at the d-line, n.sub.F represents the refractive index of the glass material of the first lens group at the F-line, n.sub.C represents the refractive index of the glass material of the first lens group at the C-line, and .nu..sub.d represents the Abbe number of the glass material of the first lens group.

Abstract: This invention relates to a microscope objective lens system a part of which is immersed in a liquid to observe a sample present in the liquid. Particularly, this invention provides an apochromat-grade microscope objective lens system which can be machined cheaply and easily by the conventional technology, which is well corrected for chromatic aberration, and which is excellent in flatness of the image plane. This objective lens system has a plane-parallel plate on the most sample side, is constructed without using an embedded lens as used in the conventional objectives, and can take a variety of lens layouts.

Abstract: An achromatic lens system includes in order, from the object side, a front lens group, a chromatic aberration correcting lens group, and a rear lens group. Aberrations, including spherical aberration, coma, astigmatism, curvature of image, as well as axial chromatic aberration of wavelengths from green to red, are substantially corrected by the front lens group and the rear lens group. The axial chromatic aberration of the wavelength blue, caused by the front lens group and the rear lens group, is corrected by the chromatic aberration correcting lens group.

Abstract: A Fourier transform lens assembly suited for use in an optical information processor includes a first lens group having a positive power, a second lens group having a negative power disposed on one side of the first lens group, and a third lens group having a positive power disposed on the side opposite to the first lens group with respect to the second lens group. The distance between a front focal plane and a back focal plane of the Fourier transform lens assembly is less than two times a focal length of the Fourier transform lens assembly.

Abstract: The invention is directed to a focusing optical system for semiconductor lasers, which is regulated in terms of magnification power in both its directions normal to the optical axis, so that the back focus of sufficient magnitude can be made equal in both the directions and the magnitude of aberration can be regulated to achieve an improvement in focusing efficiency, and in which a light beam from a semiconductor laser having varying exit angles in the horizontal and vertical directions is focused on a spot having substantially equal diameters in the horizontal and vertical directions. This focusing optical system comprises first lens unit L1 including a rotation asymmetric lens having positive power in the direction defined by a large exit angle at which a laser beam emanates from the laser, a second lens unit L2 including at least one lens of negative power, and a third lens unit L3 that is a rotation asymmetric lens unit having positive power in the directions defined by both large and small exit angles.

Abstract: An eyepiece lens system for endoscopes comprising a plurality of lens components and using at least one aspherical surface. This eyepiece lens system is composed of a small number of lens elements and has favorably corrected aberrations.

Abstract: A zoom lens for the projector includes, in order from a screen, a first lens unit of positive refractive power, a second lens unit of negative refractive power and a third lens unit of positive refractive power, zooming from the wide-angle end to the telephoto end being performed by axially moving the second and third lens units in such a manner that the air separation between the first and second lens unit increases, while the air separation between the second and third lens units decreases, and the following conditions being satisfied:1<-.beta.3w<1.50.8<-.beta.2w<1.20.25<-f2/fw<0.450.7<e2w/fw<1.1where .beta.2w and .beta.3w are the image magnifications for an infinitely distant object of the second and third lens units in the wide-angle end, respectively, f2 is the focal length of the second lens unit, e2w is the interval between the principal points of the second and third lens units, and fw is the shortest focal length of the entire lens system.