Abstract: The present disclosure provides a camera optical lens including, from an object side to an image side in sequence: eight lenses which are, from an object side to an image side in sequence: a first lens having a positive refractive power, a second having a positive refractive power, a third lens having a negative refractive power, a fourth lens, a fifth lens having a positive refractive power, a sixth lens having a positive refractive power, a seventh lens having a negative refractive power, and an eighth lens having a positive refractive power; and the camera optical lens satisfies conditions of: 0.95?f/TTL; 2.00?f2/f?5.00; and 2.50?(R15+R16)/(R15?R16)?15.00. The camera optical lens can achieve good optical performance while meeting the design requirements for ultra-thinness and long focal length.

Abstract: There are provided a subminiature optical system having a miniature size and capable of obtaining a narrow view angle using only five sheets of lenses, and a portable device having the same. The subminiature optical system includes a first lens convex toward the object side and having positive refractive power, a second lens concave toward an image side and having negative refractive power, a third lens convex toward the object side and having positive refractive power, a fourth lens concave toward the image plane and having negative refractive power, and a fifth lens convex toward the image plane and having negative or positive refractive power, sequentially from an object side.

Abstract: The present disclosure a camera optical lens comprising, from an object side to an image side, a first lens having a positive refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a negative refractive power, and a fifth lens having a positive refractive power, the second lens is bonded to the third lens, the camera optical lens satisfying conditions of 0.35?f1/f?0.75. The camera optical lens can achieve excellent optical characteristics while meeting the designing requirement for having a large aperture and a long focal length, and being ultra-thin.

Abstract: An optical photographing lens assembly includes six lens elements, in order from an object side to an image side, the six lens elements are a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element has positive refractive power. The fourth lens element has negative refractive power. The fifth lens element has an object-side surface being concave in a paraxial region thereof. The sixth lens element has an image-side surface being convex in a paraxial region thereof, both an object-side surface and the image-side surface of the seventh lens element are aspheric, and at least one of the object-side surface and the image-side surface of the sixth lens element includes at least one inflection point.

Abstract: A lens assembly includes a fifth lens, a first lens, a second lens, a third lens and a fourth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The second lens is a biconcave lens. The third lens is a biconvex lens and made of glass material. The fourth lens includes a concave surface facing the object side.

Abstract: Provided is an imaging lens. The imaging lens includes a first lens having a positive (+) power, a second lens having a positive (+) power, a third lens having a negative (?) power, and a fourth lens having a positive (+) power. The first lens, the second lens, the third lens, and the fourth lens are sequentially disposed from an object to transmit an image of light having a wavelength band of about 400 nm to about 1,000 nm. Thus, powers, distances, and Abbe's numbers of the first to fourth lenses may be controlled to photograph an image of visible light and infrared light.

Abstract: The present invention provides a mobile device and an optical imaging lens thereof. The optical imaging lens comprises an aperture stop, first, second, third and fourth lens elements positioned sequentially from an object side to an image side. The first lens element with positive refracting power has a surface facing toward the object side. The second lens element with negative refracting power has a convex surface facing toward the object. The third lens element has a positive refracting power. The fourth lens element has a surface facing toward the object side with a concave portion in the vicinity of the optical axis and a surface facing toward the image side with a convex portion in the peripheral vicinity. The optical imaging lens of the present invention is capable of shortening the total length of the optical imaging lens efficiently and has good optical characteristics.

Abstract: The disclosed internal focusing large-aperture medium telephoto lens has as lens groups a positive first lens group, a positive second lens group, and a third lens group, in that order from the object side. When focusing on nearby objects, the first lens group and the third lens group have a fixed position relative to the image surface, and the second lens group displaces toward the object side. The second lens group has only one negative lens, and, in order from the object side, has at least a positive lens, a negative lens, and a positive lens. The following expression is fulfilled: ?0.5<(R1+R2)(R1?R2)<?0.1 (wherein, R1: radius of curvature of the object side surface of the negative lens in the second lens group; R2: radius of curvature of the image side surface of the negative lens in the second lens group).

Abstract: An imaging lens includes, sequentially from an object side, a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a negative refractive power. The third lens group is configured by a single lens element, and is moved along an optical axis, whereby focusing is performed.

Abstract: An optical image system includes, in order from an object side to an image side, a first lens element with positive refractive power and having a convex object-side surface, a second lens element with positive refractive power, a third lens element with negative refractive power and having a concave object-side surface and a convex image-side surface, and a fourth lens element with refractive power and having a concave image-side surface. By such an arrangement, the total track length and photosensitivity of the image capturing lens assembly can be effectively reduced while retaining a high image quality.

Abstract: The invention relates to optics comprising adjustable optical elements and, if desired, lenses of fixed focal lens. By use of an appropriate controller for the adjustable optical elements, characteristics of the optics can be advantageously varied. For this purpose, systems are provided which are suitable for use as surgical stereo-microscope, objective, ocular or zoom. A zoomable imaging optics comprises lenses and of variable optical power, which are oppositely controlled by means of a controller to change an imaging ratio, so that the optical power of the one lens is increased and the optical power of the other lens is decreased. Moreover, the imaging optics may comprise still further assemblies of fixed optical power.

Abstract: To provide a lens system advantageous for downsizing a moving group and suitable for large aperture ratio formation and ultra telescopic formation while maintaining an excellent optical function from a long distance to a close range. A first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, and a fourth lens group having a negative refracting power are provided in order from an object side. The first lens group includes a first sub group and a second sub group. The second sub group is provided with a refracting power stronger than that of the first sub group and a following condition equation is satisfied. 1.5<f1a/f1b<2.2??(1) where, f1a denotes a focal length of the first sub group and f1b denotes a focal length of the second sub group.

Abstract: An image pickup optical system for forming a light flux from an object into an optical image on an image pickup element, is provided with, in order from an object side thereof: a first lens with a negative power in a meniscus shape including a convex surface facing the object side; a second lens in a bioconcave shape; a third lens with a positive power including a convex surface facing an image surface side; and a fourth lens with a positive power including a convex surface facing the image surface side. The first lens and the third lens are glass lenses and the second lens and the fourth lens are plastic lenses.

Abstract: A telephoto lens system includes a positive first lens group, a positive second lens group, a diaphragm, a negative third lens group constituting a focusing lens group, and a positive fourth lens group. The first lens group includes a positive first lens element, a positive second lens element, and a negative third lens element. The second lens group includes a negative or a positive fourth lens element and a positive or negative fifth lens element which are cemented to each other. The third lens group includes a positive or negative sixth lens element and a negative or positive seventh lens element which are cemented to each other. The fourth lens group includes one positive eighth lens element. Upon focusing on an object at infinity to an object at a closer distance, the third lens group is moved toward the image. The telephoto lens system satisfies the following conditions: 1.4<f/f1<1.8 ??(1) 2.4<f/f12<3.0 ??(2) ?5.5<f/f3<?3.

Abstract: To provide a lens system advantageous for downsizing a moving group and suitable for large aperture ratio formation and ultra telescopic formation while maintaining an excellent optical function from a long distance to a close range. A first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, and a fourth lens group having a negative refracting power are provided in order from an object side. The first lens group includes a first sub group and a second sub group. The second sub group is provided with a refracting power stronger than that of the first sub group and a following condition equation is satisfied. 1.5<f1a/f1b<2.2 ??(1) where, f1a denotes a focal length of the first sub group and f1b denotes a focal length of the second sub group.

Abstract: A telephoto lens system of a four-lens-group arrangement includes a negative first lens group, a positive or negative second lens group, a negative third lens group and a positive fourth lens group. The telephoto lens system of the four-lens-group arrangement is constituted by less than six lens elements in total. The positive or negative second lens group is constituted by a positive lens element and a negative lens element which are cemented to each other, in this order from the object. The positive lens element has a convex surface with a larger curvature facing toward the object. The positive or negative second lens group satisfies the following condition: 0.8<f2p/|f2n|<1.4.

Abstract: A telephoto lens includes, in order from the object side, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a negative refracting power. The second lens unit has a cemented lens composed of a positive lens and a negative lens, and a negative lens. The fourth lens unit has a cemented lens composed of a negative lens and a positive lens, and a negative lens. The telephoto lens satisfies the following conditions: ?d>80 ?0.5>f4/f>?1.2 where ?d is an Abbe's number of a lens having a positive refracting power in the first lens unit, f4 is a focal length of the fourth lens unit, and f is a focal length of the entire optical system.

Abstract: A compact optical system includes a reduced number of lens elements with a bendable optical path and so is compatible with miniature image pickup devices. The image pickup lens includes, in order from its object side, a first lens element having a negative refracting power, a second lens element having positive refracting power, a stop, a third lens element having a negative refractive power and a fourth lens element having positive refracting power, and satisfies the following conditions (1) and (2) 50>&ngr;d1−&ngr;d2>10  (1) 2>f/f3>0.35  (2) where &ngr;d1 is the d-line reference Abbe number of the first lens element, &ngr;d2 is the d-line reference Abbe number of the second lens element, f is the focal length of the image pickup lens, and f3 is the composite focal length of the third and fourth lens elements. Between the first and the second lens element there is interposed a reflecting surface.

Abstract: A telephoto lens for a grating scale measurement system includes a pair of aspheric lenses that together operate at finite conjugates with minimal spherical aberrations. Identical aspheric lenses provide a subsystem with a magnification of 1×, and a magnifying system typically including one or more negative lens increases the magnification of an intensity pattern to enable accurate measurement of the phase of the intensity pattern.

Abstract: A telescopic lens system includes a positive first lens group, and a positive second lens group. The first lens group includes cemented lens elements having a positive lens element and a negative lens element. The second lens group includes a positive lens element and a negative lens element. The telescopic lens system satisfies the following condition: 0.6<&Sgr;|S1I|/&Sgr;|S1|  (1) wherein &Sgr;|S1I| designates the total sum of the absolute values of the spherical aberration coefficients (Seidel coefficients) of the first lens group, and &Sgr;|S1| designates the total sum of the absolute values of the spherical aberration coefficients (Seidel coefficients) of the entire telescopic lens system.

Abstract: There are provided A zoom lens system comprising, in order from an object side, a first lens unit of negative refractive power, a second lens unit of positive refractive power, a third lens unit of negative refractive power, and a fourth lens unit of positive refractive power, wherein the zoom lens system zooming from a wide angle end to a telephoto end a separation between each lens units is varied so that conditional expressions D1W>D1T, D2W>D2T, and D3W>D3T are satisfied where DiW is a separation between an i-th lens unit and an (i+1)-th lens unit at a wide-angle end, DiT is a separation between an i-th lens unit and an (i+1)-th lens unit at a telephoto end, wherein a diffraction optical element is included in at least one of lens units.

Abstract: A zoom lens comprising, in the order of an increasing distance from an object; a fixed first lens group (1) having a positive refractive power; a second lens group (2) containing an aspherical surface, having a negative refractive power and being in charge of a variable power action by being moved; a fixed third lens group (3) containing an aspherical surface and having a positive refractive power; and a fourth lens group (4) containing an aspherical surface, having a positive refractive power and moving while following up a moving object point; wherein the surface on the image plane side of a lens positioned closest to the image plane in the third lens group (3) has a concave plane having a strong refractive power with respect to the image plane and a relation, 2.0<L/CL1<2.

Abstract: A variable magnification optical system includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power arranged to move along an optical axis during variation of magnification, the second lens unit including, in order from the object side to the image side, a first lens (L21) of negative refractive power and of meniscus form having a concave surface facing the image side, a second lens (L22) of negative refractive power, a third lens (L23) of positive refractive power and a fourth lens (L24) of negative refractive power, a third lens unit of positive refractive power, at least a part of the third lens unit being moved in such a way as to have a component perpendicular to the optical axis to displace an image formed by the variable magnification optical system, and a fourth lens unit of positive refractive power arranged to move along the optical axis during the variation of magnification, wherein the following condition

Abstract: A rear focus type zoom lens has, in succession from the object side, a first lens unit L1 of positive refractive power, a second lens unit L2 of negative refractive power, a third lens unit L3 of positive refractive power and a fourth lens unit L4 of positive refractive power. The second lens unit is moved toward the image plane side to effect a focal length change from the wide angle end to the telephoto end. The fourth lens unit is moved to correct the fluctuation of the image plane resulting from a focal length change and the fourth lens unit is moved to effect focusing. The third lens unit has a stop most adjacent to the image plane side. The surface thereof adjacent to the stop is convex toward the image plane side and aspherical.

Abstract: An objective optical system has at least three lens units having positive, negative, and positive optical powers. A fourth lens unit can have either negative or positive optical power.

Abstract: A high performance zoom lens system formed by multiple focus lens groups, multiple zoom lens groups and single auxiliary lens group aligned in that order on a common optical axis and arranged to collect radiation emanating from an object space and deliver that radiation to an axially stationary real image in an image space, such as on a film plane or video CCD. The multiple focus lens groups comprise a first focus lens group of negative optical power that is axially movable and contains at least one non-spherical, non-plano, optically refractive surface, and a second focus lens group of positive optical power that is axially movable. The multiple zoom lens groups comprise a first zoom lens group of negative optical power that is axially movable, and a second zoom lens group of positive optical power that is axially movable and contains an optical stop or iris.

Abstract: An optical system for use in an infrared camera which includes, in order from an object side: a first lens group having a negative refractive power and a second lens group having a positive refractive power arranged a distance from the first lens group. The first lens group comprises a negative meniscus lens having a convex surface facing toward the object side and the second lens group comprising, in order from the object side: a first lens having a positive refractive power, a second lens having a negative refractive power and a third lens having a positive refractive power. The lenses comply with the following conditions: (1) 0.5.PHI.<-.PHI.f<0.7.PHI., (2) 0.55.PHI.<.PHI.r<0.87.PHI., (3) 1.55 (1/.PHI.)<d<1.98 (1/.PHI.) and (4) dr<2.1 (1/.PHI.). The conditions are defined by: .PHI.: is the overall refractive power for the overall optical system for the infrared camera, .PHI.f: is the refractive power for the first lens group, .PHI.

Abstract: The invention provides a solution to a problem of allowing a symmetrical wide-angle lens system to have a large aperture ratio, and achieves an optical system which is well improved in terms of sagittal coma and curvature of field, and has a satisfactory vignetting factor as well. The optical system comprises basically a first lens group G1 having a negative refracting power, a second lens group G2 containing an aperture stop and having a positive negative power, and a third lens group having a negative refracting power. The second lens group G2 is divided into front and rear sub-groups G.sub.21 and G.sub.22, each having a positive refracting power, between which the aperture stop is located. The first lens group G1 comprises at least one negative meniscus lens convex on an object side; the front sub-group G.sub.21 of the second lens group comprises at least one set of cemented lens including a positive lens and a negative lens; and the rear sub-group G.sub.

Abstract: The invention provides a telephoto lens system that enables the camera operator to shoot an infinite to nearby object with stably maintained optical quality. This lens system comprises a first positive lens unit G.sub.1, a second positive lens unit G.sub.2, a third negative lens unit G.sub.3 and a fourth positive lens unit G.sub.4. The first unit comprises at least two positive lenses and a negative meniscus lens heavily concave on the image surface side; the second unit comprises a positive lens heavily convex on the object side and a doublet consisting of negative and positive lenses; the third unit comprises a doublet consisting of negative and positive lenses; and the fourth unit comprises a cemented doublet consisting of negative and positive lenses. While the first and second units remain fixed, the third and fourth units are moved for focusing. Specific conditions regarding the focal lengths of the units, the separation between adjacent units, and the amount of movement of the units are satisfied.

Abstract: A micro lens allowing a short-distance photographing operation from infinity to an equal magnification consists of, in order from the object side, a first lens group including a negative lens and having a positive refracting power, a second lens group having a positive refracting power, a third lens group including a cemented lens (doublet lens) and having a negative refracting power, and a fourth lens group having a positive refracting power. When a focusing operation is performed from infinity to a short distance, the first lens group is nonlinearly moved and the group interval between the second and third lens groups is increased, thereby satisfying required conditions.

Abstract: An internal focusing telephoto lens includes, in succession from the object side, a first lens unit of positive refractive power having at least a positive first lens component, a second lens unit having negative refractive power and movable along the optical axis for focusing, and a third lens unit having positive refractive power and having an imaging function. The first lens unit forms a substantially afocal system with the second lens unit, and is designed to satisfy the following conditions:0.43<.phi./f.sub.1 <0.750.39<f.sub.1 /F<0.55,where.phi.: the effective diameter of the object side lens surface of the positive first lens component in the first lens unit,f.sub.1 : the focal length of the first lens unit,F: the focal length of the entire system.

Abstract: A simple zoom lens is disclosed having lens units of negative, positive and negative powers in this order from the object side, zooming from the wide-angle end to the telephoto end being performed by moving each lens unit toward the object side, and at least the leading negative and positive lens units each consisting of one lens.

Abstract: A wide angle objective lens has, in succession from the object side, a first lens component which is a positive meniscus lens having its convex surface facing the object side, a second lens component which is a cemented meniscus lens comprising a negative lens and a positive lens cemented together and having its concave surface facing the object side and having positive refractive power, a third lens component which is a cemented meniscus lens comprising a negative lens and a positive lens cemented together and having its concave surface facing the object side and having positive refractive power, and a fourth lens component which is a negative meniscus lens having its concave surface facing the object side, and has a stop between the second lens component and the third lens component, and satisfies various predetermined conditions.

Abstract: An objective lens system for endoscopes comprising, in the order from the object side, a first lens component having a negative refractive power, a second lens component having a positive refractive power, an aperture stop arranged right after the second lens component, and a rear lens unit comprising a third lens component designed as a cemented doublet consisting of a lens element having a positive refractive power and a lens element having a negative refractive power. Said objective lens system for endoscopes has a wide field angle, a compact design, a small number of lens elements and favorably corrected aberrations.