Abstract: Provided is a lens optical system, which includes (from object to image side) a first lens group having positive refractive power, a stop, and a second lens group having positive refractive power. The first lens group comprises a plurality of lenses among which there are a lens closest to the object side and a lens closest to the stop having negative refractive powers. The second lens group includes a front group and a rear group.

Abstract: An optical lens system for taking image comprises, in order from the object side to the image side: an aperture stop; a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a plastic second lens element with negative refractive power having a concave object-side surface, a convex image-side surface and at least one aspheric surface; a plastic third lens element with negative refractive power having a convex object-side surface, a concave image-side surface and at least one aspheric surface. The number of the lens elements with refractive power being limited to three. Focal lengths of the optical lens system, the first lens element, the second lens element and the third lens element are f, f1, f2, f3 respectively; Abbe numbers of the first and second lens elements are V1, V2 respectively, an on-axis distance between second and third lens elements is T23, and they satisfy the relations: 0.8<f/f1<1.8; 0<|f/f2|<0.8; 0<|f/f3|<0.

Abstract: Disclosed is an image pickup lens (LN) including at least three lens blocks (BK) each equipped with a lens substrate (LS) being a parallel flat plate, and a lens or lenses (L) having a positive or negative power and being connected to at least one of an object-side surface and an image-side surface of the lens substrate (LS). In the image pickup lens (LN), a first lens block (BK1) arranged at a closest position to an object side has a positive powder, a second lens block (BK2) arranged at an image side of the first lens block (BK1) has s negative power, and predetermined conditional expressions are satisfied, whereby the image pickup lens capable of being easily produced at a low cost and having a high performance and a compact size can be provided.

Abstract: Provided are a wafer-level lens module and an image pickup module including the same. The wafer lens module includes a plurality wafer-scale lenses. At least one of the plurality of wafer-scale lenses, such as a wafer-scale lens positioned toward an object side, includes a substrate and a glass lens element formed on one side of the substrate. The glass lens element may be a one-sided lens or a double-sided lens. When the glass lens is a double-sided lens, the substrate may have a through hole. The remaining wafer-scale lenses each include a substrate and polymer lens elements made of UV curable polymer and formed on both sides of the substrate. Also, spacers are interposed between the wafer-scale lenses, along the edge portions of the substrates, so as to maintain predetermined intervals between the wafer-scale lenses.

Abstract: A wide-angle lens system includes a negative first lens group, a negative second lens group and a positive third lens group, in this order from the object. The first lens group includes a negative meniscus lens element having the convex surface facing toward the object, and a positive lens element having a convex surface facing toward the object, in this order from the object. The first lens group includes at least one aspherical surface. The second lens group includes a negative meniscus lens element having the convex surface facing toward the object, and cemented lens elements having a positive lens element and a negative lens element, in this order from the object. The third lens group includes cemented lens elements having a negative lens element and a positive lens element, and a positive lens element having a convex surface facing toward the image, in this order from the object.

Abstract: A wide-angle imaging lens is provided and includes: a first lens, a second lens, and a third lens in this order from the object side. The first lens is a negative meniscus and has a convex surface on the object side; the second lens, at least one surface of which is an aspherical surface; and the third lens is a positive lens and has a convex surface on the image side and at least one surface of the third lens is an aspherical surface. The first len is made of a material having an Abbe number of 40 or more and the third lens is made of a material having an Abbe number of 50 or more. An aperture stop is disposed between the second lens and the third lens.

Abstract: Three lenses formed of ZnS are used in combination. A first lens is a meniscus lens having a middle portion which is convex on an object side. A second lens has a middle portion that is a meniscus, which is concave on an object side and has positive refractive power, and a peripheral portion, which is convex on the object side. The first and second lenses have positive refractive power in combination. A third lens is provided adjacent to the second lens with a distance therebetween 1 mm or less and has a middle portion, which is a convex meniscus on an object side, and a peripheral portion which is concave on the object side. A diffraction surface is formed in either surface of the lens.

Abstract: An imaging lens comprises, in order from an object side: an aperture stop; a first lens having a positive refractive power in a meniscus form having a convex surface facing toward the object; a second lens having a positive or negative refractive power in a meniscus form having a concave surface facing toward the object; and a third lens having a positive or negative refractive power in an aspheric form at both surfaces, wherein conditional expressions given below are satisfied: ?d1>50??(1) ?d3>50??(2) 0.7<f1/f<1.0??(3) ?0.9<f2/{f3·(45??d2)}<0.4??(4) where ?d1: Abbe number of the first lens, ?d2: Abbe number of the second lens, ?d3: Abbe number of the third lens, f: Focal length of an overall system, f1: focal length of the first lens, f2: focal length of the second lens, and f3: focal length of the third lens.

Abstract: An imaging optical system for cameras comprising a stop, a first lens, a second lens, and a third lens in order from object side to image side. The first lens is convex at the object side, and has positive refractive power and both surfaces of which are aspherical. The second lens is convex at the image side and has negative refractive power. The third lens has a concave surface at its central portion facing the image side and a convex surface at its peripheral portions facing the image side. The imaging optical system satisfies the conditions of the following Inequalities: 0.8 < L 2 ? Y < 1 0.5 < fl f < 0.86 where L denotes the distance from the stop to the image focal point, 2Y denotes the diagonal length of the effective image surface, f denotes the overall focal distance of the imaging optical system, and f1 denotes the focal distance of the first lens.

Abstract: An optical object distance simulation device for reducing total optical path includes: a lens, an achromatic lens set, a first image lens, and a second image lens. The achromatic lens set disposes beside one side of the lens, the first image lens disposes beside one side of the achromatic lens set, and the second image lens disposes beside one side of the first image lens. The achromatic lens set is composed of a first lens and a second lens. The first lens is a double-concave lens. The second lens is a double-convex lens. One concave face of the double-concave tightly contacts with one convex face of the double-convex lens. Therefore, the lens, the achromatic lens set, the first image lens, and the second image lens match with each other in order to simulate real object distance for reducing an object distance between a test camera lens and a corresponding chart.

Abstract: A photographic lens of a photographic apparatus which includes a plurality of lens groups may be manufactured using a method which includes correcting a focus deviation from a designed value generated in one lens group by adjusting a distance between lenses of another lens group. The distance between lenses may be adjusted using a washer. The lenses between which the distance is adjusted may include a positive lens and a negative lens, and the lens group having the lenses between which the distance is adjusted may have a negative refractive power.

Abstract: The present invention provides an optical analyzer having illumination optics that include a light source, such as a laser or other source, adapted to emit a collimated, or approximately collimated, light beam, a focusing lens that focuses the beam onto a focus spot within a detection region, and beam-adjusting optics positioned in the light path between the light beam source and the focusing lens, which allow for precise positioning of the focus spot within the detection region. The beam-adjusting optics of the present invention comprise at least one movable focusing lens, mounted in a positioning device that allows repositioning of the lens in a plane perpendicular to the light path.

Abstract: A compact imaging lens system includes three lenses. The first lens is a positive meniscus lens having a convex side facing toward the image side, which has a big focusing power and is provided to capture image and for balance of aberration. The first lens serves to make the lens system a low sensitivity lens system. The second lens is a negative lens and is provided mainly for correcting chromatic aberration and off-axis aberration. An aperture is set between the first and second lenses, and this is of benefit to balance of aberration. The third lens is a negative lens and is provided for correcting off axis aberration. All the lenses can be made of plastics. This facilitates cost reduction, weight reduction, while still maintains a high resolution.

Abstract: Disclosed is an optical head apparatus comprising: a light source; a collimating means of converting a beam of light emitted from the light source into a substantially parallel beam of light; a focusing means of focusing the light onto an information medium surface; a beam splitting means of splitting the beam of light modulated by the information medium; and a light receiving means of receiving the light modulated by the information medium, wherein a lens having a negative power and a lens having a positive power are arranged in this order as viewed from the collimating means side between the collimating means and the focusing means, and at least either one of the lenses is moved along an optical axis to correct spherical aberration occurring on the information medium surface, and wherein the distance from the lens having the positive power to the focusing means is set substantially equal to the focal length of the lens having the positive power.

Abstract: An optical system includes, in order from an object side to an image side, a first lens having a negative refractive power and having a meniscus shape whose surface on the object side has a convex shape and whose surface on the image side has an aspheric shape, a second lens having a negative refractive power, and a third lens having a negative refractive power. In the optical system, a focal length of the entire optical system (f), a focal length of the first lens (f1), and respective radii of curvature of lens surfaces of the second lens on the object side and on the image side (G2R1, G2R2) satisfy the following conditions: ?1.6<f1/f<?1.2 0.1<(G2R1?G2R2)/(G2R1+G2R2)<0.5.

Abstract: A photographic lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a stop, and a third lens unit having a positive refractive power. In the photographic lens, the third lens unit moves towards the object side while the second lens unit moves towards the image side during focusing from an infinitely distant object to a closest distance object. In addition, in the photographic lens, an image forming magnification of the second lens unit during focusing on a closest distance object is appropriately set.

Abstract: Providing a compact lens system having high optical performance over the entire focusing range from infinity to a close distance, an optical apparatus equipped therewith, a method for focusing the lens system, and a method for vibration reduction of the lens system. The lens system includes, in order from an object, a first lens group G1, a second lens group G2, and a third lens group G3. Combined refractive power of the first lens group G1 and the second lens group G2 is positive. The first lens group G1 and the second lens group G2 are movable to an object side for varying focusing from the object locating at infinity to the object locating at a close distance. Each lens group includes at least one positive lens and at least one negative lens. Given conditional expressions are satisfied.

Abstract: This invention provides a photographing optical lens assembly including, in order from an object side to an image side: a first lens element with positive refractive power; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; and a third lens element with negative refractive power having a concave object-side surface, a concave image-side surface and at least one inflection point formed on the third lens element, the object-side and image-side surfaces thereof being aspheric. The first lens element may be a bi-convex lens element or a convex-concave meniscus lens element. When the first lens element is a bi-convex lens element, the refractive power thereof may be significantly enhanced to shorten the total track length of the optical system. When the first lens element is a meniscus lens element, the astigmatism of the optical system may be better corrected.

Abstract: A lens system for forming a final image of an object, said system having an object side and an image side and forming a first intermediate real image between the object and final image, said system comprising a moving lens group containing the intermediate real image as the magnification of the final image is changed. The lens system is configured as a whole system so that optical aberrations at the intermediate real image, including field curvature, focus, astigmatism, distortion and color separation, are allowed to be of substantially greater magnitude than the corresponding optical aberrations of the final image.

Abstract: Provided are a wafer scale lens, which is so short in an optical total length with respect to an image height that it can correct an aberration satisfactory, and an optical system including the wafer scale lens and having a thin lens element on the side closest to the image. The optical system includes a first lens having a positive refractive power relative to an object, and a second lens arranged on the side of the image of the first lens and having a recessed shape on the side of the object. At least one lens is arranged on the side of the second lens.

Abstract: The present invention provides a wafer-scale lens in which a total optical length is short in comparison with an image height and astigmatism and other aberrations can be well corrected, and an optical system in which a lens element closest to the object side is thin in thickness. The optical system includes a first lens that is disposed closest to the object side and is positive in refractive power; a second lens that is disposed on the image side and has a concave surface on the object side; an i-th lens, (i?3), that is disposed closest to the image side in lenses disposed on the image side and includes an i-th lens plate and a lens element which is formed on at least either the object side surface or the image side surface of the i-th lens plate, and has a refraction index different from the i-th lens plate and positive or negative refractive power; and satisfies 0.9>Ymax/Y>0.

Abstract: A three-unit zoom lens system includes in order from an object side thereof, a first lens unit G1 having a negative refracting power, a second lens unit G2 having a positive refracting power, a third lens unit G3 having a positive refracting power or a negative refracting power, and an aperture stop which is on an image plane side of the first lens unit G1, and on an object side of a lens surface nearest to the image side, of the second lens unit G2, and which moves integrally with the second lens unit. At the time of zooming from the wide angle end to the telephoto end, a distance between the first lens unit G1 and the second lens unit G2 is narrowed, and a distance between the second lens unit G2 and the third lens unit G3 changes. The second lens unit G2 moves toward the object side at the time of zooming from the wide angle end to the telephoto end. The second lens unit includes a positive lens made of plastic, which is disposed nearest to the object.

Abstract: The present invention is an imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured, the imaging lens comprising a first lens 14, an aperture stop S, a second lens 16, and a third lens 18, which are arranged in this sequence from an object side to an image side. For the first lens, a single lens is used. The second lens comprises a first sub-lens L1, a second sub-lens L2 and a third sub-lens L3, arranged in this sequence from the object side to the image side. The third lens comprises a fourth sub-lens L4, a fifth sub-lens L5 and a sixth sub-lens L6, arranged in this sequence from the object side to the image side. The first lens is formed of a transparent curable silicone resin, and the first, third, fourth and sixth sub-lenses are also formed of the transparent curable silicone resin.

Abstract: A single focus lens comprises: a first lens of positive power having a convex-shaped surface on an object side; a second lens of a negative meniscus lens having, on the object side, a concave-shaped surface on its paraxial axis; and a third lens of an aspheric lens having, on the object side, a convex-shaped surface on its paraxial axis, in this order from the object side, wherein the single focus lens satisfies the predetermined conditions.

Abstract: Reducing the outer diameter and effectively correcting various aberrations realizes a small-diameter objective optical system suitable for in vivo observation with a high numerical aperture. The invention provides a small-diameter objective optical system comprising, in order from an object plane a first lens group with positive refractive power, including at least one plano-convex lens whose convex surface faces an image plane; a second lens group with positive refractive power, including at least one concave lens; and a third lens group including a cemented lens of which a cemented surface has negative refractive power. The focal length of the third lens group is larger than the focal length of the first lens group.

Abstract: An imaging lens enables a large focal depth and low error sensitivity. The imaging lens satisfies “0.016<?/f<0.018,” where ? is the absolute value of longitudinal chromatic aberrations at F curve and C curve wavelengths, and f is the combined focal distance of the entire compound imaging lens. A first, a second, and a third lens are disposed sequentially, the first lens disposed toward an object, and the third lens disposed toward an image surface. The first lens has a positive refraction, a meniscus shape, and a convex surface facing the object. The second lens has a meniscus shape with a concave surface facing the object. The third lens has a convex-type shape facing the object; and a concave-type aspherical shape facing the image surface, providing a negative refraction in a radially central portion and a positive refraction in a radially peripheral portion.

Abstract: A zoom lens system includes, in order from an 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. During zooming from a wide-angle end to a telephoto end, a space between the first lens unit and the second lens unit narrows, at least the second lens unit moves only toward the object side, and the third lens unit is constituted of one positive lens.

Abstract: An optical system used for an image pickup apparatus including an image pickup element is provided. The optical system includes a negative lens disposed furthest away on the enlargement conjugation side and satisfies the following condition: 80 degrees<2?, where 2? (degrees) denotes an angle of view of the optical system. In addition, the following parameters of the optical system are optimally determined: a lens open angle ? of a surface of the negative lens on the reduction conjugation side, an index of refraction Ndn and an Abbe number ?dn of a material of the negative lens for a d-line, and a relative partial dispersion ?gFn of the material of the negative lens for a g-line and an F-line.

Abstract: Provided is a camera module. The camera module includes an aperture stop, a first lens, a second lens, a third lens, and an image sensor. The first lens has a positive refractive power to transmit light that has passes through the aperture stop, and the second lens has a negative refractive power to transmit light that has passed through the first lens. The third lens has a negative refractive power to transmit light that has passed through the second lens. The image sensor detects light that has passed through the third lens.

Abstract: A lens unit includes a first lens having positive power, a second lens having positive power, an aperture stop, a third lens having negative power, and a fourth lens. The first lens, the second lens, the aperture stop, the third lens, and the fourth lens are arranged in order from an object side toward an image side.

Abstract: An imaging lens includes, in order from an object side, a first lens having a negative power and including a concave image-side surface, a second lens having a positive power, a stop, a third negative lens, which is a biconcave lens, a fourth lens having a positive power, and a fifth lens having a positive power and including a convex image-side surface. The imaging lens satisfies the following conditional expressions: 0.18<(D4+D5)/f<0.44, and 0.18<D1/f where f denotes a focal length of an entire lens system, D1 denotes a thickness of a center of the first lens, D4 denotes a distance from an image-side surface of the second lens to the stop on an optical axis, and D5 denotes a distance from the stop to an object-side surface of the third lens on the optical axis.

Abstract: Described is a wide-angle slip-on viewfinder (1) on rangefinder cameras for analog and digital wide-angle recordings of different image recording formats with lenses of different focal lengths, comprising three lens groups (LG1, LG2, LG3), a frame/mask unit (10) and a partially transmissive prism cube (8) which is designed as a combination element, wherein, on the light entrance side (4) in the viewfinder beam path (9), a first lens group (LG1) has a negative refractive power and the second and third lens groups (LG2, LG3) have a positive refractive power, wherein the second lens group (LG2) is composed of a first lens (L3) arranged downstream of the first lens group (LG1) and a second lens (L4) arranged on the light exit side (7) and the partially transmissive prism cube (8) is arranged between the lenses (L3, L4) and the third lens group (LG3) is arranged in a mask imaging beam path (11) which is at right angles to the viewfinder beam path (9) between the frame/mask unit (10) and the partially transmissive

Abstract: An imaging lens includes: in order from an object side, an aperture diaphragm; a first lens of a positive lens having a convex surface on the object side; a second lens of a meniscus lens having a concave surface on the object side; and a third lens. The imaging lens satisfies: f/f3<0.95 and BR2<0. BR2 satisfies BR2=A/D4, A represents a distance from a vertex position on a object-side surface of the second lens and on an optical axis to a position on a image-side surface of the second lens through which a light ray passes toward a corner of an image height, provided that a traveling direction of the light ray is taken as appositive direction, and D4 represents a center thickness of the second lens. f represents a focal length of the imaging lens. f3 represents a focal length of the third lens.

Abstract: A wide-angle optical system comprises, in order from its object side, a stop, a first lens (L1) having positive refracting power, a second lens (L2) having negative refracting power and a third lens (L3) that is an aspheric lens. The third lens is configured such that as viewed in a lens section including an optical axis, a portion thereof near the optical axis is in a meniscus shape convex on an object side thereof, and an object side surface and an image side surface thereof at a peripheral site are in a meniscus shape convex on an image side thereof. The optical system satisfies the following conditions (1-1) and (1-2). ?0.40<f/f3<0.15??(1-1) 0.30<hc7/hp7<2.0??(1-2) where f is the focal length of the whole wide-angle optical system, and f3 is the focal length of the third lens.

Abstract: An optical lens system for taking image consisting of three lens elements with refractive power, in order from the object side to the image side: a meniscus first lens element with positive refractive power having a convex object-side surface; an aperture stop; a meniscus plastic second lens element with negative refractive power having a convex image-side surface, and the object-side surface and the image-side surface of the second lens element being both aspheric, the Abbe number of the second lens element being V2, and it satisfying the relation: V2>40; a meniscus plastic third lens element with negative refractive power having a convex object-side surface, the object-side surface and the image-side surface of the third lens element being both aspheric, an Abbe number of the third lens element being V3, and it satisfying the relation: V3>40.

Abstract: A pickup lens is provided with various aberrations corrected satisfactorily, with a short optical length, and with a sufficient back focus secured. The configuration comprises an aperture diaphragm S1, first lens L1, second lens L2, and third lens L3, and is configured by arranging, in order from the object side to the image side, the aperture diaphragm, first lens, second lens, and third lens. The first lens is a lens having positive refractive power, with convex surfaces on the object side and on the image side. The second lens is a lens having negative refractive power, in a meniscus shape with the convex surface on the image side. The third lens is a lens having negative refractive power, in a meniscus shape with the convex surface on the object side. Both of the surfaces of the first lens are aspherical, both of the surfaces of the second lens are aspherical, and both of the surfaces of the third lens are aspherical.

Abstract: A zoom lens system comprising, in order from an object along an optical axis: 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; the following conditional expression being satisfied: 0.6<Ymax×ft/f12<1.0 where Ymax denotes the maximum image height of the zoom lens system, ft denotes a focal length of the zoom lens system in a telephoto end state, and f1 denotes a focal length of the first lens group.

Abstract: Disclosed are a projection lens that is faster than F1.95 and has a simple inner focus structure, a high optical performance, and a small size, and a projection display device. A projection lens 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 arranged in this order from a magnification side. A fifth lens arranged closest to a reduction side in the first lens group is moved along an optical axis to adjust focus. The projection lens satisfies the following conditional expression: 0.2<DG12/f<0.8 where DG12 indicates a distance between the first lens group and the second lens group and f indicates the focal length of the entire lens system.

Abstract: An imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured. This imaging lens comprises a first junction type compound lens 14, an aperture diaphragm S, a second junction type compound lens 16, and a third junction type compound lens 18, wherein the first junction type compound lens, the aperture diaphragm, the second junction type compound lens, and the third junction type compound lens are arranged in this sequence from an object side to an image side.

Abstract: A color image readout lens comprises, in order from an object side: a first group comprising a positive lens convex toward the object side and a biconcave negative lens; a stop; a second group comprising one diffractive optical element that has at least one flat surface and has a diffractive structure formed on the flat surface; and a third group comprising a biconvex positive lens and a negative lens concave toward the object side.

Abstract: Disclosed is a projection variable focusing lens and a projection display device that has a reduction side which is telecentric, a high magnifying power, a small size, a light weight, and a low manufacturing cost and is capable of correcting all aberrations occurring when power varies with good balance. A projection variable focusing lens that moves only one lens group when power varies includes a first negative lens group G1, a second positive lens group G2, and a third positive lens group G3, arranged in this order from a magnification side. When a focal length varies, only the second lens group G2 is moved along an optical axis X. During focusing, the first lens group G1 is moved along the optical axis X. A reduction side is substantially telecentric.

Abstract: A cemented lens comprises first, second and third optical elements respectively formed by different solid materials, the third and first optical elements being cemented to each other, and the first and the second optical elements being cemented to each other, wherein both an incident surface and an exit surface of the first and second optical elements are refracting surfaces, and the following conditional expressions are satisfied: |??gF1|>0.0272 |??gF2|>0.0272 ??gF1×??gF2<0 ?1×?<0 where ??gF1 and ??gF2 are respectively anomalous dispersion characteristics of the materials for the first and the second optical elements with respect to a g line and an F line, and ?1 and ?2 are respectively refracting powers of the first and second optical elements when both the incident surface and the exit surface of the first and the second optical element are surfaces in contact with air.

Abstract: A microscope objective lens is disclosed that includes, in order from the object side, a first lens group having positive refractive power, a second lens group having positive refractive power that is movable along the optical axis, and a third lens group. The first lens group includes, in order from the object side, two meniscus lens components, each with its concave surface on the object side, and at least one positive lens component, and the third lens group has adjacent concave lens element surfaces that face each other and are in contact with air. Specified conditions may be satisfied, and one or more lens components in the first lens group and the second lens group may be movable.

Abstract: A three-unit zoom lens includes, in order from the object side, a negative first lens unit G1, a positive second lens unit G2 and a third lens unit G3, wherein during zooming from the wide angle end to the telephoto end the distance between the first lens unit G1 and the second lens unit G2 decreases and the distance between the second lens unit G2 and the third lens unit G3 changes. The first lens unit G1 is composed of one negative lens component including, in order from the object side, a negative lens having a concave surface directed toward the image side and a positive lens having a convex surface directed toward the object side. The second lens unit G2 includes at least one negative lens and a plurality of positive lenses, wherein at least three lenses among these lenses are cemented to adjacent lenses, the total number of lens components included in the second lens unit G2 is two or less. The third lens unit is composed of one lens component composed of two or less lenses.

Abstract: A lens barrel including a first moving lens group for advancing light of a subject onto an image plane, a second moving lens group for advancing light of the subject onto the image plane, a shaft section for guiding the first moving lens group and the second moving lens group in a direction of an optical axis, an intermediate positioning section for supporting the shaft section at an intermediate portion of the shaft section, and an end positioning section for supporting one end of the shaft section, wherein the first moving lens group slides on a portion of the shaft section that is closer to the subject than the intermediate positioning section is, and wherein the second moving lens group slides on a portion of the shaft section that is closer to the image plane than the intermediate positioning section is.

Abstract: An optical system in which a maximum value of a height from an optical axis of a paraxial marginal ray closer to an expanded side than a point of intersection between an optical axis and a paraxial chief ray, includes a lens unit Lr including at least one refractive optical element Gn of a negative refractive power. In the optical system, ?d (Gn) as an Abbe number of a material of the refractive optical element Gn, ?gF (Gn) as a partial dispersion ratio regarding g and F-lines, FGn as a focal lengths of the refractive optical element Gn, and Fr as focal lengths of the lens unit Lr are set appropriately.

Abstract: An imaging lens is provided and includes: in order from an object side of the imaging lens, a first lens having a positive refractive power; a second lens having one of a positive refractive power and a negative refractive power; and a third lens that corrects for aberration. At least one of the first and second lenses has a diffractive optical surface, the diffractive optical surface having twenty or less orbicular gratings in a range to pass an effective light ray.

Abstract: An imaging apparatus, configured to form an image on an image pickup element, includes, in an order from an object side toward an image side, a first optical unit having a negative refractive power, a second optical unit having a positive refractive power, and a third optical unit including the image pickup element. The first optical unit does not move during zooming. The second optical unit moves toward the object side and the third optical unit moves.

Abstract: An image projection apparatus includes an image processing device, an illuminating device, a light valve, and a projection optical system; wherein the projection optical system is formed in such a way that at least one of a first deviation corresponding to an amount of the magnification chromatic aberration of a light having a central wavelength of the red light relative to the green light and a second deviation corresponding to an amount of the magnification chromatic aberration of the blue light relative to the green light is larger than a fixed-pixel pitch, and a third deviation corresponding to an amount of the magnification chromatic aberration of a light having a maximum wavelength of the red light relative to a light having a minimum wavelength of the red light is not larger than the fixed-pixel pitch; wherein the first deviation and/or the second deviation is eliminated by supplying the compensated video signal to the light valve.

Abstract: The present invention provides an image pickup lens for forming an image of an object on a photoelectrical converter of a solid-state image pickup element. The image pickup lens includes: an aperture stop; a first lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex; a second lens having a negative refractive power whose surface facing an image side of the image pickup lens is concave; and a third lens having a positive refractive power and having a meniscus shape whose surface facing the object side is convex. Each of the first lens, the second lens, and the third lens includes an aspheric optical surface. The image pickup lens satisfies predetermined conditions according to a focal length of the first lens, and a refractive power of an air lens formed from surfaces of the second lens and the third lens.