Abstract: An imaging optical system has, in order from the object side to the image side thereof, a front lens group, an aperture stop, and a rear lens group. A lens located closest to object side in said front lens group always remains fixed in position, with satisfaction of the following conditions (1) and (2): 1.15?fb/IH??1.7 ??(1) ?4.0?fn/f??1.3 ??(2) where f is a focal length of the whole imaging optical system, fn is a focal length of a first negative lens in said front lens group, fb is a back focus of the imaging optical system upon focusing on an object point at infinity, and IH? is a distance from an optical axis of a position where a chief ray from a maximum incident half angle of view (?) upon focusing on an object point at infinity is imaged at the imaging plane.

Abstract: A lens system, in an order from the object side thereof to the image side thereof, includes an aperture stop, a first lens having positive refractive power, a second lens having positive refractive power. The lens system satisfies the formulae: Rmax/TTL>0.97; and 0.31<G1R1/F1<0.33, wherein Rmax denotes the largest imaging circle diameter of the lens system, TTL denotes the total track length of the lens system, G1R1 denotes the curvature radius of the vertex of the first object-side surface, F1 denotes the focal length of the first lens.

Abstract: An imaging lens includes an optical system having in order from an object side to an image side a first lens group having a positive refractive power and a second lens having a positive refractive power to image an optical image of an object, the first lens group and the second lens group being displaced in an extending amount different from one another to be focused on an object of a finite distance, the first lens group including a negative meniscus lens having a convex surface on the object side, a lens having a weak refractive power, and a lens having a positive refractive power, and the second lens group including four lenses or less or five lenses or less having at least one pair of a cemented lens.

Abstract: An imaging optical system, including a first lens group; an aperture stop; a second lens group having a positive power, the first lens group, the aperture stop and the second lens group being arranged from a side of an object sequentially, wherein the second lens group includes a second front lens group having a positive power and a second rear lens group having a positive power, the second front lens group and the second rear lens group being arranged sequentially from the object side, wherein, when focusing from an infinity-distance object to a short-distance object, the first lens group and the aperture stop are fixed, and the second front lens group and the second rear lens group are moved with a mutually different movement amount.

Abstract: An endoscope illumination optical system includes a surface light source, a positive first lens element, a positive second lens element, in this order from the surface light source. The endoscope illumination optical system satisfies the following conditions: 0.40<f/D<0.53??(1) 0.40<0.5·D·?<0.56??(2) wherein f: the combined focal length of the positive first lens element and the positive second lens element; D: the maximum diameter of the surface light source; R1: the radius of curvature of a first surface, of the positive first lens element, facing toward the surface light source; R2: the radius of curvature of a second surface, of the positive first lens element, facing toward a surface to be illuminated; n1: the refractive index of the positive first lens element; d1: the thickness of the positive first lens element; and ? designates an angle defined as (1+0.85d1/R2)(1?1/n1)/R1?1.05/R2.

Abstract: A scanning objective lens for scanning on an observation target with light emitted from an exit end face of an optical fiber moving on a curved plane formed to be convex on an objective lens side, including first and second lens groups each having a positive power, wherein the first lens group and the second lens group are arranged in this order from the optical fiber's exit end face side, and the scanning objective lens satisfies conditions: 0.60<f1/f2<1.25??(1); and 0.95<|R1a/R1b|<2.50??(2) when f1 denotes a focal length of the first lens group, f2 denotes a focal length of the second lens group, R1a denotes a curvature radius in the first lens group nearest to the exit end face of the optical fiber, and R1b denotes a curvature radius of a lens surface in the first lens group nearest to the observation target.

Abstract: An image pickup lens includes: a first lens group including a single negative lens and a single positive lens disposed in order from the object side to the image side and having a positive refracting power; and a second lens group having a positive refracting power. The first and second lens groups are disposed in order from the object side to the image side. The first lens group is fixed, when the image pickup object distance varies from the infinity to the proximity, with respect to an image surface while the second lens group is moved from the image side to the object side to carry out focusing.

Abstract: An image-forming lens includes: from an object side to an image side in order, a first group with a positive refractive power which includes less than or equal to five lens elements of two negative lenses and equal to or more than two positive lenses and in which a first lens element on a most object side is a negative meniscus lens a convex surface of which faces the object side; an aperture; and a second group with a positive refractive power which includes less than or equal to five lens elements including at least one cemented lens of a positive lens and a negative lens; wherein each of the first group and the second group shifts independently to perform focusing to a limited object distance, and an interval between the first lens element and a second lens element close to a surface on the image side of the first lens element: d11-2 and an interval between the second lens element and a third lens element close to a surface on the image side of the second lens element: d12-3 satisfy Conditional Expression

Abstract: An integrated micro-optical system includes at least two wafers with at least two optical elements provided on respective surfaces of the at least two wafers, at least one of the two optical elements being a spherical lens. The resulting optical system presents a high numerical aperture. One of the optical elements may be a refractive element formed in a material having a high index of refraction.

Abstract: An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12<f/f1<0.47 and 0.016<D12/f<0.079 are satisfied, when f1 is a focal length of the first lens group, f is a focal length of the imaging lens, and D12 is an air distance between the first lens component and the second lens component of the first lens group.

Abstract: An eye model including a front positive lens, a rear positive lens, an aperture stop located between the front and rear positive lenses, and a focal plane located rearward of the rear positive lens, wherein the front positive lens has a meniscus shape having an outer surface radius equal to a radius of a human eye, and wherein the rear positive lens has a rear surface having a radius equal to a distance from the aperture stop to the rear surface.

Abstract: An objective optical system includes, in order from the object side, a first unit having two lenses with negative refracting power and positive refracting power, a stop, and a second unit with positive refracting power to satisfy the following condition: 3.0<fb/fL where fb is the back focus of the objective optical system in air and fL is the focal length of the entire objective optical system.

Abstract: An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12<f/f1<0.47 and 0.016<D12/f<0.079 are satisfied, when f1 is a focal length of the first lens group, f is a focal length of the imaging lens, and D12 is an air distance between the first lens component and the second lens component of the first lens group.

Abstract: An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12<f/f1<0.47 and 0.016<D12/f<0.079 are satisfied, when f1 is a focal length of the first lens group, f is a focal length of the imaging lens, and D12 is an air distance between the first lens component and the second lens component of the first lens group.

Abstract: An optical lens system for taking image comprises, in order from an object side to an image side: a first lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface; a second lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface. Radii of curvature of the object-side surface of the first lens element, the object-side and image-side surfaces of the second lens element are R1, R3 and R4 respectively, focal lengths of the optical lens system for taking image, the first and second lens elements are f, f1, f2 respectively, an on-axis distance between the first and second lens elements is T12, a center thickness of the second lens element is CT2, they satisfy the relations: 0.76 mm?1<1/R1<2.0 mm?1; 0.4<R3/R4<1.15; 0.35<(f/f1)?(f/f2)<0.72; T12/CT2>1.0.

Abstract: An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12<f/f1<0.47 and 0.016<D12/f<0.079 are satisfied, when f1 is a focal length of the first lens group, f is a focal length of the imaging lens, and D12 is an air distance between the first lens component and the second lens component of the first lens group.

Abstract: A wide-angle lens LN consists of, in order from an object side: a first lens group Gr1 having positive refractive power; and a second lens group Gr2 having positive refractive power; the second lens group Gr2 is movable toward the object side with fixing the first lens group Gr1, thereby carrying out focusing on a close object, and a given conditional expression is satisfied. Therefore, a wide-angle lens having high optical performance with suppressing variation in aberrations upon focusing in spite of being a large aperture, an imaging optical apparatus equipped therewith, and a digital equipment are provided.

Abstract: Providing an optical system having excellent optical performance over entire focusing range from infinity to a close distance, a method for focusing the optical system, and an imaging apparatus equipped therewith. The optical system includes, in order from an object, a first lens group G1 having positive refractive power, and a second lens group G2 having positive refractive power. The second lens group G2 is movable along an optical axis for varying focusing. The first lens group G1 satisfies a given conditional expression.

Abstract: An imaging optical system, including a first lens group; an aperture stop; a second lens group having a positive power, the first lens group, the aperture stop and the second lens group being arranged from a side of an object sequentially, wherein the second lens group includes a second front lens group having a positive power and a second rear lens group having a positive power, the second front lens group and the second rear lens group being arranged sequentially from the object side, wherein, when focusing from an infinity-distance object to a short-distance object, the first lens group and the aperture stop are fixed, and the second front lens group and the second rear lens group are moved with a mutually different movement amount.

Abstract: Providing a compact rear-focus optical system having excellent optical performance, an imaging apparatus, and a method for focusing the rear-focus optical system. The system includes, in order from an object, a first lens group G1 having positive refractive power, an aperture stop S, and a second lens group G2. At least a portion of the second lens group G2 is movable along an optical axis of the rear-focus optical system upon focusing. Given conditional expressions are satisfied.

Abstract: An imaging lens includes, in order from an object side, a first lens group having a positive power, an aperture diaphragm, and a second lens group having a positive or negative power. The first lens group includes, in order from the object side, a first lens which is a biconcave lens, a second lens that has a positive power and includes a convex image-side surface, and a third lens that has a positive power and includes a convex object-side surface. The second lens group includes, in order from the object side, a fourth lens that has a negative power and includes a concave image-side surface, and a fifth lens which is a biconvex lens. Each of the first to fifth lenses is a single spherical glass lens.

Abstract: Provided is an optical system (PS) which is used in a wavelength range including a near ultraviolet light range having a wavelength longer than approximately 350 nm and a visible light range. The optical system includes at least two first positive lenses which satisfies a predetermined conditional expression concerning anomalous dispersion characteristic and a rate of change of the refractive index with respect to temperature, and is disposed closer to a contraction side than an aperture stop (ST), and at least one second positive lens which satisfies a predetermined conditional expression concerning anomalous dispersion characteristic and a rate of change of the refractive index with respect to temperature.

Abstract: A two-lens type optical lens system for taking image consists two lens elements with refractive power, from the object side: a positive first lens element with a convex object-side surface and a concave image-side surface, both the object-side surface and the image-side surface of the first lens element being aspheric; a positive second lens element with a concave object-side surface and a convex image-side surface, both the object-side surface and the image-side surface of the second lens element being aspheric, and an aperture stop located in front of the first lens element. A focal length of the first lens element is f1, a focal length of the second lens element is f2, a focal length of the optical lens system is f, a radius of curvature of the object-side surface of the second lens element is R3, and they satisfy the relations: f/f1>0.9; (f/f1)>(f/f2)>0.35; and 1/R3<?0.01 mm?1.

Abstract: An imaging optical system, including a first lens group; an aperture stop; a second lens group having a positive power, the first lens group, the aperture stop and the second lens group being arranged from a side of an object sequentially, wherein the second lens group includes a second front lens group having a positive power and a second rear lens group having a positive power, the second front lens group and the second rear lens group being arranged sequentially from the object side, wherein, when focusing from an infinity-distance object to a short-distance object, the first lens group and the aperture stop are fixed, and the second front lens group and the second rear lens group are moved with a mutually different movement amount.

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 an object side to an image side: a first lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface; a second lens element with positive refractive power having an aspheric convex object-side surface and an aspheric concave image-side surface. Radii of curvature of the object-side surface of the first lens element, the object-side and image-side surfaces of the second lens element are R1, R3 and R4 respectively, focal lengths of the optical lens system for taking image, the first and second lens elements are f, f1, f2 respectively, an on-axis distance between the first and second lens elements is T12, a center thickness of the second lens element is CT2, they satisfy the relations: 0.76 mm?1<1/R1<2.0 mm?1; 0.4<R3/R4<1.15; 0.35<(f/f1)?(f/f2)<0.72; T12/CT2>1.0.

Abstract: An image taking lens LA comprises an aperture S1, a first lens L1 and a second lens L2 which are arranged in this order from an object side to an image side. The first lens L1 has a positive power and a meniscus shape with a convex surface facing an object; and the second lens L2 has a positive power with a convex surface facing an image. The first lens L1 and the second lens L2 satisfy the following formulae (1) and (2): 0.30<R1/R2<0.65??(1) 0.30<d3/F<0.50??(2) This image taking lens formed of the two lenses is small in size and has a high optical performance, in which the entire image taking lens has a short focal length.

Abstract: A system and method for collimating light emitted from a light source, such as a light-emitting diode (LED), is provided. The system and method includes two lenses, both lenses having a positive power for converging the light rays. In one example, the first lens is a hemispherical ball lens and the second lens is configured such that one surface conforms to the exiting surface of the first lens. The exiting surface of the second lens may be, for example, a Fresnel lens or an aspherical lens. In another example, the first lens may be a hemispherical or a hyperhemispherical ball lens. The second lens has an outer circumference having two aspherical surfaces. The inner portion of the second lens is in direct contact with the first lens. This configuration creates a dual-channel collimator.

Abstract: An objective optical system includes, a first group having positive refractive power, a second group having positive refractive power, the first group having a first parallel flat plate, a diaphragm, a second parallel flat plate and a first plano-convex lens with its convex surface facing the image side in the above mentioned order as viewed from the object side, the first parallel flat plate, the second flat parallel plate and the first plano-convex lens forming a cemented lens, the second parallel flat plate being formed by an infrared absorption filter, the second group having a second plano-convex lens with its convex surface facing the object side.

Abstract: A wide angle lens module includes a first lens and a second lens with negative refracting power, a third lens and a fourth lens with positive refracting power, a fifth lens with negative refracting power, a sixth lens with positive refracting power, and a seventh lens with negative refracting power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are assembled in order from an object side to an image side.

Abstract: The invention relates to a focus detection optical system for digital single-lens reflex cameras or the like and an imaging apparatus incorporating the same. A pupil division optical system comprises an aperture stop having a pair of openings with an optical axis of said taking lens held between them, and a pair of re-imaging lenses, each consisting of a double-convex lens having a convex entrance-side surface and a convex exit-side surface.

Abstract: It is to provide an imaging lens that has excellent optical performance while being compact and light. The imaging lens includes, in order from an object side to an image surface side, a diaphragm, a first lens that is a meniscus lens having a positive power whose convex surface faces the object side, and a second lens that is a meniscus lens having a positive power whose convex surface faces the image surface side, wherein a condition expressed by ?30.5?r3/d3??19 (where, r3: center radius curvature of the object side face of the second lens, and d3: center thickness of the second lens is to be satisfied.

Abstract: An objective optical system for endoscopes is characterized by comprising, in order from its object side, a stop, a first lens and a second lens. The first lens comprises a positive meniscus lens concave on its object side and the second lens comprises a positive lens convex on its object side. The following conditions (1), (2), (3) and (4) are satisfied: ?1.2<r1/f<?0.8??(1) ?1.0<r2/f<?0.6??(2) 2.1<f2/f<4.2??(3) nd1>1.65??(4) where r1 is the radius of curvature of the object-side surface of the first lens, r2 is the radius of curvature of the image-side surface of the first lens, f is the focal length of the whole optical system, f2 is the focal length of the second lens, and nd1 is the d-line refractive index of the first lens.

Abstract: A lens system comprising an inner lens structure and an outer lens structure. The inner lens structure comprises an inner positive lens, a first transparent substrate and an inner negative lens. The outer lens structure comprises an outer positive lens, a second transparent substrate and an outer negative lens.

Abstract: An optical system is mounted in a mobile communication terminal and a personal digital assistant (PDA) for a monitoring camera and a digital camera. The optical system includes: a first optical element formed in a meniscus shape entirely convex toward an object and having a positive refractive power; and a second optical element having an object-side surface convex toward the object and an image-side surface formed of a plane, wherein the second optical element includes: a fourth optical element having an object-side surface entirety convex toward the object on the optical axis; and a fifth optical element having an object-side surface in contact with an image-side surface of the fourth optical element, and an image-side surface and an object-side surface formed of planes respectively.

Abstract: An imaging lens including, in order from an object side to an image surface side, a first lens that is a meniscus lens having a positive power whose convex surface faces the object side, a diaphragm, a second lens that is a meniscus lens having a positive power whose convex surface faces the image surface side, wherein conditions expressed by 22?(r3+r4)/(r3?r4)?35 and 0.5?f1/fl?1 (where, r3: center radius curvature of the object side face of the second lens, r4: center radius curvature of the image surface side face of the second lens, f1: focal distance of the first lens, and fl: focal distance of the entire lens system) are to be satisfied.

Abstract: An imaging lens includes, in order from an object side, a first lens group having a positive power, an aperture diaphragm, and a second lens group having a positive or negative power. The first lens group includes, in order from the object side, a first lens which is a biconcave lens, a second lens that has a positive power and includes a convex image-side surface, and a third lens that has a positive power and includes a convex object-side surface. The second lens group includes, in order from the object side, a fourth lens that has a negative power and includes a concave image-side surface, and a fifth lens which is a biconvex lens. Each of the first to fifth lenses is a single spherical glass lens.

Abstract: An imaging lens includes, in order from an object side, a positive first lens group, a stop, and a positive second lens group. The first lens group includes, in order from the object side, a first lens, which is a negative meniscus lens having a convex object-side surface, and a second lens having a positive power and including a convex image-side surface. The second lens group includes, in order from the object side, a third lens having a negative power and including a concave object-side surface, a fourth lens having a positive power and including a convex image-side surface, a fifth lens, which is a biconvex lens, and a sixth lens, which is a meniscus lens having a negative power and including a convex surface facing an image side. Each of the first to sixth lenses is a single spherical glass lens.

Abstract: Providing an optical system having a large aperture ratio, a long back focal length, high optical performance with excellently correcting various aberrations, and an optical apparatus equipped with the optical system. The system includes, in order from an object along an optical axis of the optical system, a first lens group having positive refractive power, and a second lens group having positive refractive power. The second lens group includes a negative lens, a first positive lens, and a second positive lens, and the optical system includes a compound type aspherical lens constructed by a glass material and a resin material.

Abstract: An objective optical system for endoscopes is characterized by comprising, in order from its object side, a stop, a first lens and a second lens. The first lens comprises a positive meniscus lens concave on its object side and the second lens comprises a positive lens convex on its object side. The following conditions (1), (2), (3) and (4) are satisfied: ?1.2<r1/f<?0.8??(1) ?1.0<r2/f<?0.6??(2) 2.1<f2/f<4.2??(3) nd1>1.65??(4) where r1 is the radius of curvature of the object-side surface of the first lens, r2 is the radius of curvature of the image-side surface of the first lens, f is the focal length of the whole optical system, f2 is the focal length of the second lens, and nd1 is the d-line refractive index of the first lens.

Abstract: An article includes an optical device. The optical device includes a first lens and a second lens. The first lens includes an optically active material that responds to an external stimulus that affects a refractive index of at least a portion of the first lens. A method for making a method of use of the article is also provided.

Abstract: An imaging lens system, in order from the object side to the image side thereof, includes a first lens with positive refractive power, and a second lens with positive refractive power. The imaging lens system satisfies the following formulas: 1.2?TTL/f?2.0, where image sensing element TTL is the distance along an optical axis thereof from the object-side lens surface of the first lens to an imaging plane, f is the focal length of whole the image lens system.

Abstract: There is provided a wide-angle lens system having a wide angle of view and less distortion. The wide-angle lens system including: an object-side lens group disposed at an object side with respect to an aperture stop and having overall positive refractive power; and an image-side lens group disposed at an image side with respect to the aperture stop and having overall positive refractive power, wherein a focal length ratio between the object-side lens group and the image-side lens group satisfies following condition 1, 2<FO/FI<10??condition 1, where FO is a focal length of the object-side lens group (FO>0) and FI is a focal length of the image-side lens group (FI>0). This wide-angle lens system sufficiently corrects distortion even in a wide angle of view, thereby ensuring an image with superior quality.

Abstract: A zoom lens comprises: a stationary group that is stationary at the time of variable power; and a variable power group, disposed on an image side of the stationary group, that makes a variable power operation by moving in an optical axis direction at the time of variable power, wherein the stationary group comprises: a first lens group including a negative meniscus lens and a positive lens and having a positive refractive power as a whole; and a second lens group, disposed on the image side of the first lens group, including: a negative lens group including a negative meniscus lens and a positive lens; and a positive lens group including at least one positive lens, in order from an object side, the second lens group having a positive refractive power as a whole.

Abstract: Providing a large aperture wide-angle lens having high optical performance with sufficiently suppressed spherical aberration and sagittal coma flare, and an imaging apparatus using the lens. The lens including, in order from an object, a first lens group having positive refractive power, and a second lens group having positive refractive power, the second lens group being movable for focusing and including a 21 lens component having positive refractive power, a 22 lens component having negative refractive power, a 23 lens component having positive refractive power, and a 24 lens component having positive refractive power, and given conditions being satisfied.

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 eye model including a front positive lens, a rear positive lens, an aperture stop located between the front and rear positive lenses, and a focal plane located rearward of the rear positive lens, wherein the front positive lens has a meniscus shape having an outer surface radius equal to a radius of a human eye, and wherein the rear positive lens has a rear surface having a radius equal to a distance from the aperture stop to the rear surface.

Abstract: An objective optical system includes, a first group having positive refractive power, a second group having positive refractive power, the first group having a first parallel flat plate, a diaphragm, a second parallel flat plate and a first plano-convex lens with its convex surface facing the image side in the above mentioned order as viewed from the object side, the first parallel flat plate, the second flat parallel plate and the first plano-convex lens forming a cemented lens, the second parallel flat plate being formed by an infrared absorption filter, the second group having a second plano-convex lens with its convex surface facing the object side.

Abstract: An imaging lens unit comprising, in order from the object side, a first lens having a meniscus shape with its convex surface on the object side, an aperture stop and a second lens having a meniscus shape with its convex surface on the image side. A maximal value of a tangent angle within a range of a lens surface effective diameter of the surface on the object side of the first lens is 70 to 90 degrees. A maximal value of a tangent angle within a range of a lens surface effective diameter of the surface on the image side of the second lens is 70 to 90 degrees.

Abstract: A lens system includes a first lens and a second lens formed in turn from an object side to an image side. The lens system satisfies the following conditions: 0.08?D2/D?0.14??(1) 4?h2/z2?12??(2) wherein, D2 is the distance along an optical axis of the lens system from the second surface of the first lens to the third surface of the second lens, D is the distance along an optical axis of the lens system from the first surface of the first lens to fourth surface of the second lens, h2 is the distance from the optical axis of the lens system to the outermost optically effective portion of the second lens surface of the first lens, and z2 is the distance along the optical axis of the lens system from the vertex of the second surface of the first lens to the point of the optical axis where h2 is measured.