Abstract: An optical system includes a first focusing unit and a second focusing unit that move in different loci during focusing. In a first arrangement state, the first focusing unit and the second focusing unit are so arranged to generate a first aberration while maintaining an in-focus state at a predetermined object distance, and in a second arrangement state, the first focusing unit and the second focusing unit are so arranged to generate a second aberration different from the first aberration while maintaining the in-focus state at the predetermined object distance.

Abstract: A four-piece optical image capturing system is disclosed. In order from an object side to an image side, the optical image capturing system along the optical axis includes a first lens with positive refractive power; a second lens with refractive power; a third lens with refractive power; and a fourth lens with refractive power; and at least one of the image-side surface and object-side surface of each of the four lenses are aspheric. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: The present technology relates to an imaging apparatus capable of offering useful information with higher certainty. An imaging apparatus includes an optical system that condenses light received from a subject, an imaging device that photoelectrically converts the light received from the optical system to form a pickup image, and a cover glass disposed between the optical system and the imaging device to protect a surface of the imaging device. The cover glass is disposed obliquely to the imaging device. When stray light corresponding to light reflected on the imaging device enters the cover glass as a part of light having entered the imaging device via the optical system and the cover glass, this stray light is reflected on the cover glass toward a low harmful area of the imaging device. Accordingly, flares generated by stray light decreases in a recognition useful area. The present technology is applicable to an on-vehicle camera, a ceiling type monitoring camera, or others.

Abstract: Provided is an observation optical system including: an objective lens; an image inverting unit; and an ocular lens, the objective lens including, in order from object side to observation side: a positive first lens unit; a negative second lens unit; and a positive third lens unit, wherein the first lens unit consists of a positive front unit and a positive rear unit separated by an air interval, which is largest along optical axis, wherein the second lens unit moves to have a component orthogonal to optical axis for image blur correction, and wherein a lateral magnification of second lens unit, a curvature radius of a lens surface of second lens unit closest to observation side, a curvature radius of a lens surface of third lens unit closest to object side, the air interval between front and rear units, and a focal length of first lens unit are appropriately set.

Abstract: An imaging-lens substantially consists of a first-lens-group, a stop and a second-lens-group in this order from object-side. The first-lens-group substantially consists of three or less lenses including a negative-lens having meniscus-shape with convex-surface facing object-side and a positive-lens cemented on the negative-lens in this order from object-side. The second-lens-group substantially consists of a 21st-lens-group substantially consisting of a 21-1st-lens and a 21-2nd-lens and a 22nd-lens-group substantially consisting of a positive-lens. The 21-1st-lens is a positive-lens, an image-side-lens-surface of which has convex-shape facing image-side, and the absolute-value of a curvature-radius of the image-side-lens-surface of which is less than the absolute-value of a curvature-radius of an object-side-lens-surface thereof.

Abstract: An image capturing lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has refractive power. The second lens element with positive refractive power has a convex image-side surface in a paraxial region thereof. The third lens element with negative refractive power has a concave object-side surface in a paraxial region thereof and a convex image-side surface in a paraxial region thereof. The fourth lens element with refractive power has a concave image-side surface in a paraxial region thereof, wherein both of an object-side surface and the image-side surface thereof are aspheric, and the image-side surface thereof has at least one convex shape in an off-axis region thereof. The image capturing lens system has a total of four lens elements with refractive power.

Abstract: A wide-angle image lens, in the order from the object side to the image side thereof, includes a first lens, a second lens, a third lens, a fourth lens and an image plane. The image lens satisfies the following formulas: D/TTL>0.45; CT4/ET4<2.11; Z/Y>0.06; wherein D is the maximum image diameter of the image plane; TTL is a total length of the wide-angle image lens; CT4 is a distance along an optical axis from the seventh surface to the eighth surface; ET4 is a distance along the optical axis from an outmost edge of the seventh surface to an outmost edge of the eighth surface; Z is a distance from a central point of the fifth surface to an outmost edge of the sixth surface along the optical axis; Y is a distance from the outmost edge of the sixth surface to the optical axis.

Abstract: This invention provides an optical lens assembly comprising, in order from an object side to an image side: a first lens element with positive refractive power; a second lens element with positive refractive power; a third lens element with negative refractive power having a concave object-side surface and a convex image-side surface, at least one of the object-side and image-side surfaces thereof being aspheric; and a fourth lens element with positive refractive power having an aspheric object-side surface and an aspheric image-side surface; wherein the number of lens elements with refractive power is four.

Abstract: An optical lens assembly for image taking, sequentially from an object side to an image side along an optical axis comprises: the first lens element with refractive power, a bi-convex second lens element with positive refractive power, the third lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the fourth lens element with positive refractive power having a convex object-side surface and a concave image-side surface. All four lenses may be made of plastic with bi-aspherical surfaces. Additionally, the optical lens assembly for image taking satisfies conditions to shorten the total length and reduce the sensitivity in order to achieve the goal of a fine aberration correction and ready for its use in cameras and camera mobile phones.

Abstract: An exemplary internally focusing lens system includes, in order from the object side to the image side, a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power. The third lens group includes one lens element. The second lens group is movable toward the image side and the first and third lens groups remain stationary during focusing of the lens system from an infinitely distant object to a nearby object.

Abstract: An imaging lens includes in order from an object side: a first lens including a positive lens having a convex surface directed to the object side; a stop; a second lens including a positive lens having a convex surface directed to an image side; a third lens including a negative meniscus lens with a concave surface directed to the object side; and a fourth lens including, near an optical axis, a positive meniscus shape with a convex surface directed to the object side. An air space between the second lens and the third lens is smaller in a periphery than near the optical axis. And f1>f2>|f3| and 1.0<f/f2<1.5 are satisfied where f1, f2 and f3 are focal lengths of the first lens, the second lens, and the third lens, respectively and f is an focal length of the whole lens system.

Abstract: A lens system for a miniature camera includes an imager and four cylindrical lenses disposed concentrically on an optical axis of the lens system. The lenses include, in order from a front end of the lens system to a back end thereof, a first lens, a second lens, a third lens and a fourth lens. The first lens has a positive power and aspheric front and back surfaces, the second lens has a negative power and aspheric front and back surfaces, the third lens is made of glass, has a positive power, a plano front surface and a spherical convex back surface, and the fourth lens has a negative power and aspheric front and back surfaces.

Abstract: A single focus imaging lens comprises: a front lens group including one or two lenses and having a positive refractive power as a whole; a rear lens group including two or three lenses and having a negative refractive power as a whole; and a focusing lens, disposed between the front lens group and the rear lens group, that has a positive refractive power and moves on an optical axis for adjusting focus, wherein the following conditional expression is satisfied: 1.0<FL/f<5.0??(X) where f: focal length of the single focus imaging lens; FL: focal length of the focusing lens.

Abstract: An imaging lens includes in order from an object side: a first lens including a positive lens having a convex surface directed to the object side; a stop; a second lens including a positive lens having a convex surface directed to an image side; a third lens including a negative meniscus lens with a concave surface directed to the object side; and a fourth lens including, near an optical axis, a positive meniscus shape with a convex surface directed to the object side. An air space between the second lens and the third lens is smaller in a periphery than near the optical axis. And f1>f2>|f3| and 1.0<f/f2<1.5 are satisfied where f1, f2 and f3 are focal lengths of the first lens, the second lens, and the third lens, respectively and f is an focal length of the whole lens system.

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 a positive refractive power and being a spherical glass lens having a convex surface on an image side thereof; a third lens having a negative refractive power and having a concave surface on the object side in the vicinity of an optical axis thereof; and a fourth lens having a positive refractive power and having a meniscus shape in the vicinity of the optical axis thereof, a convex surface in the meniscus shape being directed to the object side, the imaging lens satisfying a specific condition.

Abstract: An image pickup lens system has a four-lens configuration which forms an image on a solid-state image pickup device. The image pickup lens system includes, from an object side, a positive first lens, an aperture stop, a positive second lens, a negative third lens whose concave surface is faced toward an image surface side, and a positive fourth lens in the order from an object side. A ratio of an axial lens thickness of the third lens to a focal length of the whole system is optimally set. Therefore, an exit pupil position can be kept far away from the image surface while the image pickup lens system has good optical performance and a compact size.

Abstract: A lens assembly suitable for use in miniature cameras is disclosed. The lens assembly can have a plurality of glass lenses having spherical surfaces and a single plastic lens having aspheric surfaces, for example. Optionally, all of the lenses can be disposed within a common lens barrel. A pupil plane can be located just in front of the first lens to provide a small chief ray angle. Both the cost of the lens assembly and alignment sensitivity are advantageously mitigated.

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 a positive refractive power and being a spherical glass lens having a convex surface on an image side thereof; a third lens having a negative refractive power and having a concave surface on the object side in the vicinity of an optical axis thereof; and a fourth lens having a positive refractive power and having a meniscus shape in the vicinity of the optical axis thereof, a convex surface in the meniscus shape being directed to the object side, the imaging lens satisfying a specific condition.

Abstract: Providing a zoom lens system that satisfies making the focusing lens light and reducing a moving amount for focusing, simultaneously. The zoom lens system includes a first lens group having positive power, a second lens group having negative power and a third lens group having positive power. When zooming from a wide-angle end state to a telephoto end state, at least the first and third lens groups are moved such that a distance between the first and second lens groups increases, and a distance between the second and third lens groups decreases. The first lens group is composed of a front lens group with positive power having at least one negative lens and at least one positive lens, and a rear lens group with positive power having one positive lens. Focusing from infinity to a close object is carried out by moving only the rear lens group to the object.

Abstract: At least one exemplary embodiment is directed to a zoom lens which includes, in order from an object side to an image side, a first lens unit having positive refractive power and is stationary during zooming, a second lens unit configured to move to perform zooming, a third lens unit configured to move to compensate for variation of an image plane caused by zooming, and a fourth lens unit having positive refractive power and is also stationary during zooming. The first lens unit includes, in order from the object side to an image side, a first lens subunit having positive refractive power and is stationary during focusing, a second lens subunit having positive refractive power, and a third lens subunit having negative refractive power and is also stationary during focusing. The second lens subunit moves along an optical axis during focusing.

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: An optical system comprises, at least, in order from an object side, a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power, wherein at least, the second lens group and the fourth lens group move along an optical axis when magnification is changed from a wide angle end to a telephoto end, and the first lens group contains a light path reflecting element having refracting power.

Abstract: A lens assembly in a camera includes a first meniscus lens (10) and a second meniscus lens (11) respectively having a first radius of curvature (A,A?) and a second radius of curvature (B,B?) larger than that of the first radius of curvature A,A?), a concave lens (12) having a first radius of curvature (C) and a second radius of curvature (C?) smaller than the first radius of curvature (C), and a convex lens (13) having two opposite sides with a radius of curvature so that after a distance between the lens to the object is determined, a clear image is presented.

Abstract: The image forming optical system of the present invention comprises, in order from an object side, a first lens which is meniscus lens having positive refracting power and a concave surface directed toward an object side, an aperture stop, a second lens having positive refracting power and a convex surface directed toward the object side, a third lens which is meniscus lens having negative refracting power and a convex surface directed toward an image side, and a fourth lens having positive refracting power.

Abstract: An imaging optical system has a variable magnification optical system. The variable magnification optical system includes, in order from the object side, a first lens unit with positive refractive power, a second lens unit with positive refractive power, a third lens unit with negative refractive power, a fourth lens unit with positive refractive power, and an aperture stop interposed between the third lens unit and the fourth lens unit. The variable magnification optical system changes an imaging magnification while keeping an object-to-image distance constant. The imaging magnification is changed by varying spacing between the first lens unit and the second lens unit, spacing between the second lens unit and the third lens unit, and spacing between the third lens unit and the fourth lens unit. When the imaging magnification is changed, the imaging optical system satisfies the following conditions in at least one variable magnification state: |En|/L>0.

Abstract: An image pickup lens has four lenses arranged in an order of a first lens, a second lens, a third lens and a fourth lens from an object side. The first lens has positive refractive power and has a convex surface facing toward an object side, the second lens has the positive refractive power, the third lens has negative refractive power and has a concave surface facing toward the object side to be formed in a meniscus shape, and the fourth lens has the positive or negative refractive power and has a convex surface facing toward the object side to be formed in the meniscus shape.

Abstract: The invention relates to an image-formation lens system for reading images, etc., which has an image-formation magnification of less than 1×, comprises a reduced number of lenses, has a short length and compactness, and is fabricated with improved image quality yet at low cost. The image-formation lens system of the four-unit type comprises, in order from its object side toward its image side, a first lens L1 having positive power, a second lens L2 having positive power, a third lens L3 having negative lens and a fourth lens L4 having positive power. The image-formation lens system satisfies conditions (1) and (3) with respect to the Abbe numbers of L1 and L3 and conditions (2) and (4) with respect to the refractive indices of L2 and L4.

Abstract: An image forming optical system includes, comprises, in order from the object side toward the image side, a first lens unit with positive refracting power, a second lens unit with positive refracting power, a third lens unit with negative refracting power, a fourth lens unit with positive refracting power, and an aperture stop interposed between the third lens unit and the fourth lens unit. The image forming optical system has a variable magnification optical system in which spacings between these lens units are changed to vary the imaging magnification, changes the imaging magnification while constantly keeping the object-to-image distance of the image forming optical system, and in at least one variable magnification state where the imaging magnification is changed, satisfies the following conditions: |En|/L>0.4 |Ex|/|L/&bgr;|>0.

Abstract: A color image readout lens having four lens groups of positive, positive or negative, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element having a convex surface on the object side. The second lens group has a convex surface of the object side and is formed of a biconvex lens element that is cemented to a biconcave lens element. The third lens group is formed of a fourth lens element that is cemented to a fifth lens element, with the fifth lens element having positive refractive power and a convex surface on the image side. A fourth lens group is formed of a sixth lens element having a convex surface on the image side. Various conditions are satisfied in order to favorably correct the various aberrations.

Abstract: A color image readout lens having four lens groups of positive, positive or negative, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element having a convex surface on the object side. The second lens group has a convex surface of the object side and is formed of a biconvex lens element that is cemented to a biconcave lens element. The third lens group is formed of a fourth lens element that is cemented to a fifth lens element, with the fifth lens element having positive refractive power and a convex surface on the image side. A fourth lens group is formed of a sixth lens element having a convex surface on the image side. Various conditions are satisfied in order to favorably correct the various aberrations.

Abstract: In an imaging lens suitable for image reading of a four-lens element configuration comprising, successively from the object side, positive, positive, negative, and positive lenses, at least one surface of the fourth lens is made aspherical, whereby lighter weight and lower cost are achieved, while various kinds of aberration are corrected. The four-lens element imaging lens comprises, successively from the object side, positive first and second lenses L.sub.1 and L.sub.2 each having a surface on the object side convex toward the object side, a negative third lens L.sub.3 having a surface on the image side concave toward the image side, and a positive fourth lens L.sub.4 having at least one aspheric surface.

Abstract: A compact variable focal length optical system is suitable for high zoom ratio. At least a first lens group having a positive refractive power, a second lens group, and a third lens group having a negative refractive power are provided. At least the first lens group is moved toward an object side of the system to satisfy a particular conditional equation so that a distance between the first and second lens groups is increased and a distance between the second and third lens groups is changed. In certain constructions, a first lens group having a positive refractive power, a second lens group having a negative refractive power positioned adjacent to and on an object side of the first lens group, and a third lens group positioned adjacent to and on an image side of the first lens group are provided. The first lens group includes at least two sub-lens groups.

Abstract: An imaging lens system consisting of a front lens unit which comprises a negative lens component disposed on the image side and has a positive refractive power, and a rear lens unit which is composed of a positive lens component: a distance ffb as measured from an object side surface of the rear lens unit to a front focal point of the rear lens unit, a distance D as measured from an exit pupil of the front lens unit to an object side surface of the rear lens unit, and refractive powers of the front lens unit and the rear lens unit being adequately defined for the imaging lens system.

Abstract: In a Xenotar type image-readout lens of a four-group five-element configuration, predetermined conditional expressions are satisfied so as to attain a bright lens system, while favorably correcting chromatic aberration. In a Xenotar type lens system composed of five sheets of lenses (L.sub.1 to L.sub.5), the second lens (L.sub.2) and the third lens (L.sub.3) are cemented together, a stop (i) is disposed between the third lens (L.sub.3) and the fourth lens (L.sub.4), and the following conditional expressions are satisfied:1.78.ltoreq.N.sub.1, 47.0<.upsilon..sub.3 +.upsilon..sub.4 <57.0, 1.4<f.sub.123 /f<2.0, 22<.upsilon..sub.2 -.upsilon..sub.3,1.37<.vertline.f.sub.2 /f.sub.3 .vertline.<1.64, 1.24<R.sub.42 /R.sub.41 <1.37, 33<.upsilon..sub.5 .times.(N.sub.

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 imaging optical system which is designed so as to be connecatable and disconnectable to and from an image guide, and arranged in a camera control unit. This imaging optical system is arranged between an image guide attached to the camera control unit and an image pickup device accommodated in the camera control unit in a condition integrated with said members, equipped with no eyepiece lens, used exclusively with a monitor TV and designed as a zoom lens system.