Abstract: An imaging lens includes first, second, third, and fourth lens elements arranged from an object side to an image side in the given order. The first lens element has a positive refractive power. The second lens element has a negative refractive power, and concave object-side and image-side surfaces. The third lens element has a positive refractive power. The fourth lens has a curved object-side surface with a convex portion and a concave portion. The imaging lens satisfies AAG/CT3?1.3, where AAG is a sum of distances between any adjacent two of the lens elements, and CT3 is a thickness of the third lens element.

Abstract: An imaging lens includes plastic-made first, second, third, and fourth lens elements arranged in the given order from an object side to an imaging side. The first lens element has a positive focusing power and is biconvex. The second lens element has a negative focusing power, is biconcave, and has an abbe number not greater than 30. The third lens element has a positive focusing power and has a convex imaging-side surface facing toward the imaging side. The fourth lens element has an imaging-side surface formed with a concave area in a vicinity of an optical axis of the fourth lens element. The imaging lens further includes an aperture stop disposed between the first and second lens elements.

Abstract: A zoom lens including a first lens unit having a positive refractive power, a second lens unit having a negative reflective power, a third lens unit having a positive refractive power, and a rear lens group including one or more lens units in this order from an object side to an image side, wherein distances between the respective lens units vary during the zooming operation, wherein the first lens unit consists of three lenses including one negative lens, and a partial dispersion ratio of a material for the negative lens of the first lens unit, an Abbe number of the same, a focal length of the entire system at a wide angle end and a focal length of the first lens unit are set individually and adequately.

Abstract: An optical lens assembly with a filter member for image taking, sequentially arranged from an object side to an image side along an optical axis, comprises: a filter member and a lens assembly. The lens assembly is set at the object side of the filter member. The lens assembly comprises at least three lens elements with refractive powers, wherein at least two lens elements are made of plastic, and have at least one aspheric object-side surface or image-side surface. By such arrangements, the optical lens assembly with a filter member for image taking can have good chromatic aberration correction and reduce the total length for applications to electronic products such as cameras and mobile phones requiring high resolution.

Abstract: An image pickup optical system having four lenses includes in order from an object side, a first lens having a biconvex shape, and a positive refractive power, a second lens having a biconcave shape, and a negative refractive power, a third lens having a meniscus shape with a concave surface thereof directed toward the object side, and a positive refractive power, and a fourth lens having a biconcave shape, and a negative refractive power, and a diaphragm is disposed nearest to the object side, and the surface on the object side of the fourth lens does not have a point of inflection as well as the optical system satisfying the recited numerical conditions.

Abstract: An image capturing lens system includes four lens elements with refractive power, 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 positive first lens element has a convex object-side surface at a paraxial region. The negative second lens element has a concave object-side surface at a paraxial region and an image-side surface changing from concave at a paraxial region to convex at a peripheral region, wherein the surfaces of the second lens element are aspheric. The positive third lens element has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region. The negative fourth lens element has an image-side surface changing from concave at a paraxial region to convex at a peripheral region, and the surfaces of the fourth lens element are aspheric.

Abstract: This invention provides an optical image capturing lens assembly comprising four lens elements, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a plastic third lens element with positive 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 plastic fourth lens element with negative refractive power, an object-side surface and an image-side surface thereof being aspheric, at least one inflection point being formed on at least one of the object-side and image-side surfaces thereof. With the aforementioned arrangement, the total track length of the lens assembly can be effectively reduced, the sensitivity of the system can be attenuated and the image quality can be improved.

Abstract: A lens optical system includes first to fourth lenses that are sequentially arranged from an object, and which are between the object and an image sensor on which an image of the object is formed. The first lens has a positive refractive power and an incident surface that is convex toward the object. The second lens has a negative refractive power and both surfaces that are concave. The third lens has a positive refractive power and has a meniscus shape that is convex toward the image sensor. The fourth lens has a negative refractive power and at least one of an incident surface and an exit surface thereof is an aspherical surface. The lens optical system may satisfy an inequality that 0.5<|tan ?|/f<1.5, where “?” denotes an angle of view of the lens optical system and “f” denotes a focal length of the lens optical system.

Abstract: An image pickup lens for a solid-state image pickup element includes a first lens having a positive refractive power with a convex surface facing the object side, a second lens with concave surfaces facing the object side and an image side, a third lens of a meniscus shape having a positive refractive power with a convex surface facing the image side, and a fourth lens with concave surfaces facing the object side and the image side, wherein the image pickup lens satisfies the following conditional expressions (1),(2),(5),and(7); ?1.3<r1/r2<0.03 ??(1) 0.09<r6/r5<1.0 ??(2) ?0.16270?r8/r7??0.0049871 ??(5) 0.38659694?f3/f?0.565293 ??(7) where r1, r2: curvature radius of the first lens; r5, r6: curvature radius of the third lens; r7, r8: curvature radius of the fourth lens; f: composite focal length of an overall image pickup lens system; and f3: focal length of the third lens.

Abstract: This invention provides a photographing optical lens assembly, from an object side to an image side in order, comprising a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave image-side surface, a third lens element with positive refractive power, a fourth lens element with negative refractive power having a concave image-side surface, both the two surfaces of the fourth lens thereof being aspheric. And an aperture stop is positioned between the first element and the second lens element. There are four lens elements with refractive power in the lens assembly.

Abstract: An image forming optical system of four lenses includes in order from an object side, a first lens having a positive refractive power, which is a biconvex lens, a second lens having a negative refractive power, of which, an image-side surface is a concave surface, a third lens having a positive refractive power, which is meniscus-shaped with a concave surface directed toward the object side, a fourth lens having a negative refractive power, of which, an image-side surface is a concave surface, and an aperture stop which is disposed nearest to the object side. The image forming optical system satisfies predetermined conditional expressions.

Abstract: An exemplary embodiment of the present invention relates to an imaging lens, the imaging lens including, in an ordered way from an object side, a first lens having positive (+) refractive power, a second lens having negative (?) refractive power, a third lens having positive (+) refractive power, a fourth lens having negative (?) refractive power, wherein the imaging lens meets a conditional expression of D4?D3?0, where D3 is a distance from an apex of an object side surface of the third lens to an apex of an image-forming surface, and D4 is an axial distance from the apex of an object side surface of the third lens to an effective diameter of an object side surface of the fourth lens.

Abstract: An imaging lens apparatus comprises four lenses with refractive power by which lead the light from the object side to the image side: a first lens with a convex object-side surface and positive refractive power, at least one surface of the first lens is aspheric; an aperture stop set next to the first lens; a second lens which is a biconcave lens with negative refractive power, at least one surface of the second lens is aspheric; a third lens which is a positive meniscus lens with a concave object-side surface, both side of the third lens are aspheric; and a fourth lens which is a negative meniscus lens with a convex object-side surface, both side of the fourth lens are aspheric with at least one inflection point; and the imaging lens apparatus satisfy the conditions below: |1/slope_S8|>0.9; ?0.2<SAG_S8<0.1.

Abstract: An image pickup lens includes, in sequence from an object side to an image side, an aperture stop; a first lens having two convex surfaces and having a positive refractive power; a second lens in a meniscus shape whose convex surface faces to the object side having a negative refractive power; a third lens in a meniscus shape with the convex surface facing to the image side having a positive refractive power; a fourth lens in a meniscus shape with the convex surface facing to the object side having a negative refractive power. Predefined conditions are satisfied.

Abstract: An imaging optical system, an imaging device, and a digital apparatus have a four lens construction with positive, negative, positive, and negative refractive powers. A surface position at the maximum effective diameter of the second lens element is located on the object side than a surface vertex thereof. The fourth lens element has an inflection point at a position other than the intersection of the optical axis and the fourth lens element. The optical system satisfies the following conditions. 0.7<f1/f<5 ?0.8<(RS1+RS2)/(RS1?RS2)<3 ?3<(RS3+RS4)/(RS3?RS4)<2 0.03<d2/TL<0.2 2W>72 ?4>50,and 0.55<Y/TL<0.

Abstract: An image pickup lens comprises a first lens (L1) having a positive refractive power, an aperture stop (s3), a second lens (L2) having a negative refractive power and having a concave surface facing the image side, a third lens (L3) having a positive refractive power, and a fourth lens (L4) having a negative refractive power and having a concave surface facing the image side. The image pickup lens satisfies predetermined formulae.

Abstract: Embodiments are disclosed herein related to the construction of optical elements for an RGB camera system. One disclosed embodiment provides a wide-angle lens construction, comprising a first, negative stage, and a second, positive stage positioned behind the first, negative stage along an optical axis of the lens construction. The second, positive stage further comprises a first positive lens substage, a first negative lens substage, a second positive lens substage, and a second negative lens substage.

Abstract: This invention provides a photographing optical lens assembly, from an object side to an image side in order, comprising a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave image-side surface, a third lens element with positive refractive power, a fourth lens element with negative refractive power having a concave image-side surface, both the two surfaces of the fourth lens thereof being aspheric. And an aperture stop is positioned between the first element and the second lens element. There are four lens elements with refractive power in the lens assembly.

Abstract: Providing for a fixed focus optical system exhibiting extended depth of field is provided herein. By way of example, a compact and fast optical system that yields an asymmetric modulation transfer function (MTF) is disclosed. In some aspects, the asymmetric MTF results in extended depth of field for near field objects. Such a response can be particularly beneficial for small handheld cameras or camera modules having high resolution. According to some disclosed aspects, the resolution can be about 8 mega pixels. Additionally, the optical system can comprise four lenses in one aspect and five lenses in another, while remaining below about 5.3 mm total track length (TTL) for the respective systems. In at least one application, the disclosed optical systems can be employed for a high resolution compact camera, for instance in conjunction with an electronic computing device, communication device, display device, surveillance equipment, or the like.

Abstract: A lens optical system includes first, second, third, and fourth lenses that are arranged between an object and an image sensor, in order from an object side, wherein the first lens has positive refractive power and an incident surface that is convex toward the object, the second lens has negative refractive power and both surfaces of which are concave, the third lens has positive refractive power and a meniscus shape that is convex toward the image sensor, and the fourth lens has negative refractive power and at least one of an incident surface and an exit surface of which is an aspherical surface, wherein the system satisfies the inequality, 3.0<TTL/BL<3.4, wherein TTL is a distance from the incident surface of the first lens to the image sensor and BL is a distance from the exit surface of the fourth lens to the image sensor.

Abstract: This invention provides an image lens system comprising: a first lens element with positive refractive power; a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric and made of plastic; a third lens element with positive refractive power; and a fourth lens element with negative refractive power, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein, the region of the image-side surface of the second lens element near the optical axis is concave, but the off-axis region thereof is convex. By such arrangement, not only the photosensitivity and total track length of the system can be reduced, but also better image quality can be obtained.

Abstract: An imaging lens includes, from an object-side to an image-side: an aperture stop, a first lens of positive refractive power with two convex surfaces along the optical axis of the imaging lens, a meniscus second lens of negative refractive power with a convex surface on the object-side, a meniscus third lens of positive refractive power with a convex surface on the image-side, a meniscus fourth lens of negative refractive power with a convex surface on the object-side. Specified conditions are satisfied in order to reduce aberrations and an Fno (focal ratio number) and enhance wide-angle view.

Abstract: An image capturing lens assembly comprises, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element with refractive power, a third lens element with positive refractive power having a convex image-side surface, and a fourth lens element with refractive power having a convex object-side surface and a concave image-side surface. The object-side surface and the image-side surface of the fourth lens element are aspheric and have at least one inflection point.

Abstract: A photographing optical lens assembly includes, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power, a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, and a fourth lens element with negative refractive power having a concave object-side surface.

Abstract: An imaging lens includes: an aperture stop; a first lens having a positive refractive power; a second lens having a negative refractive power which is formed in a concave shape on both sides thereof; a third lens having a positive refractive power which is formed in a meniscus shape in which a concave surface is directed toward the side of an object; and a fourth lens having a negative refractive power in which a convex surface is directed toward the object side, which are sequentially disposed from the object side to the image side, wherein the imaging lens satisfies the following conditional expressions (1), (2), (3), (4) and (5): 0.40<f1/|f2|<0.80??(1) 0.80<|f2|/f3<1.50??(2) 0.90<f/|f4|<2.00??(3) 2.60<|(R2?R3)/f1|<4.00??(4) ?d1??d2>25.

Abstract: An imaging lens, including in order from an object side to an image side, an aperture stop, a first lens formed in a biconvex shape having a positive refractive power, a second lens having a negative refractive power with a surface on the image side formed to be a concave surface, a third lens having a positive refractive power with a convex surface faced to the image side, and a fourth lens having a negative refractive power with a surface on the image side formed to be a concave surface.

Abstract: An image pickup lens compatible with small high-pixel image pickup elements (e.g., from CCD and CMOS image sensors having a pixel pitch of 1.75 ?m and a pixel count of 5 mega pixels to CCD and CMOS image sensors having a pixel pitch of 1.4 ?m and a pixel count of 8 mega pixels) is provided. An image pickup lens 7 includes, in order from an object side to an image surface side: an aperture stop 5, a first lens 1 having positive power; a second lens 2 that is a meniscus lens having negative power and whose lens surface facing the image surface side is concave; a third lens 3 that is a meniscus lens having positive power and whose lens surface facing the image surface side is convex; and a fourth lens 4 that has negative power, whose lens surfaces are both aspherical and whose lens surface facing the image surface side is concave near the optical axis. A diffractive optical element is formed on one of the lens surfaces of the first lens 1 or the second lens 2.

Abstract: In an image forming optical system which includes in order from an object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, an aperture stop, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a negative refractive power, and in which, at the time of zooming, air distances between lens groups are variable, and an air lens nearest to an image side in the third lens group G3 has a shape of a convex lens, the fourth lens group G4 includes one lens component, and is movable even at the time of focusing, and satisfies the following conditional expressions 0.5<(R4F+R4R)/(R4F?R4R)<8.0??(1) ?12.0<(R4LAF+R4LAR)/(R4LAF?R4LAR)<?2.0??(2).

Abstract: A lens optical system having first to fourth lenses sequentially arranged from an object, and between the object and an image sensor on which an image of the object is formed. The first lens has a positive refractive power and is convex toward the object. The second lens has a negative refractive power and is biconcave. The third lens has a positive refractive power and is convex toward the image sensor. The fourth lens has a negative refractive power and at least one of an incident surface and an exit surface of the fourth lens is an aspherical surface. An aperture may be arranged between the first and second lenses.

Abstract: An imaging lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, and a fourth lens element with negative refractive power having a concave object-side surface and a concave image-side surface. The third lens element and the fourth lens element are aspheric. The fourth lens element has at least one inflection point. By adjusting the distance between the second lens element and the first lens element as well as the thickness of the second lens element, the imaging lens assembly can be easy to be manufactured and assembled without decreasing its imaging quality.

Abstract: An optical element includes an effective diameter area that is centered on an optical axis and transmits an effective light beam, and a flange portion having, on a side surface around the effective diameter area, a slope that is not perpendicular to a direction of the optical axis.

Abstract: An optical image lens assembly 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 with positive refractive power has a convex object-side surface. The second lens element has refractive power. The third lens element with refractive power is made of plastic material, wherein an object-side surface and an image-side surface of the third lens element are aspheric. The fourth lens element with negative refractive power is made of plastic material, and has a concave image-side surface, wherein an object-side surface and the image-side surface of the fourth lens element are aspheric, and the fourth lens element has at least one inflection point formed on at least one of the object-side surface and the image-side surface thereof.

Abstract: A photographing optical lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface, and a fourth lens element having a convex object-side surface and a concave image-side surface with both surfaces thereof being aspheric.

Abstract: An image pickup lens capable of providing an angle of view of up to 70° or higher is provided. The image pickup lens can also be reduced in size and various aberrations associated with the lens can be corrected favorably, so that the image pickup lens is compatible with a high-pixel image pickup element. The image pickup lens 7 includes, in order from an object side to an image surface side: a first lens 1 that is a biconvex lens having positive power; a second lens 2 that has negative power and whose lens surface facing the image surface side is concave; a third lens 3 that is a meniscus lens having positive power and whose lens surface facing the image surface side is convex; and a fourth lens 4 that has negative power, whose lens surfaces are both aspherical and whose lens surface facing the image surface side is concave near an optical axis.

Abstract: Provided is a lens module for imaging an object on an image plane. In the order from the object side to the image side of the lens module, the lens module includes a first lens made of glass and having positive refraction power, a second lens made of plastic and having negative refraction power, a aperture stopper, a third lens having positive refraction power, and a fourth lens having negative refraction power. The lens module satisfies the following formula: Vd1?Vd2?35; wherein, Vd1 is the Abbe number of the first lens in d light and Vd2 is the Abbe number of the second lens in the d light.

Abstract: To provide an image sensing lens and an image sensing module each of which includes four lenses and each of which corrects aberrations well and has a great resolving power and a reduced height, an image sensing lens includes (i) a third lens which has a surface facing an image surface, the surface being an aspheric surface and (ii) a fourth lens which has a surface facing an object and a surface facing the image surface, the surfaces being each an aspheric surface. The image sensing lens satisfies the following Formulae (1) through (3): 0.51<f1/f<0.78??(1) ?1.63<f2/f<?0.97??(2) v1?v2>20??(3).

Abstract: An image pickup optical system having five lenses includes in order from an object side, a first lens having a biconvex shape, and a positive refractive power, a second lens having a negative refractive power, a third lens having a meniscus shape with a concave surface thereof directed toward the object side, and a negative refractive power, a fourth lens having a meniscus shape with a concave surface thereof directed toward the object side, and a positive refractive power, and a fifth lens having a negative refractive power. The third lens and the fourth lens are cemented, and the negative refractive power at a central portion of the third lens increases gradually toward a peripheral portion thereof, and the positive refractive power at a central portion of the fourth lens decreases gradually toward a peripheral portion thereof.

Abstract: This invention provides an optical imaging lens system in order from an object side to an image side including: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface, a third lens element with positive refractive power, and a fourth lens element having a concave image-side surface, and at least one of the object-side and image-side surfaces thereof being aspheric; wherein the optical imaging lens system further comprises an aperture stop and an electronic sensor on which an object is imaged, and the aperture stop is positioned between an object and the first lens element; wherein there are four lens elements with refractive power. By such arrangement, total track length and photosensitivity of the optical imaging lens system can be effectively reduced while retaining high image quality.

Abstract: A lens system, in the order from the subject side to the image side thereof, includes an aperture stop, a first lens of positive refractive power, a second lens of negative refractive power, a third lens of positive refractive power, and a fourth lens of negative refractive power. The image lens satisfies the formulae: G2R2<G2R1<0; and 0<D1/D2<9.95, where G2R1 is the curvature radius of the subject-side surface of the second lens, G2R2 is the curvature radius of the image-side surface of the second lens, D1 is the diameter of the aperture stop, and D2 is the distance from the center of the aperture stop to the center of the subject-side surface of the first lens.

Abstract: The present invention relates to an optical system for a camera. The optical system for a camera in accordance with the present invention includes: a first lens that has a positive refractive index and has a convex shape toward an object; a second lens that has a negative refractive index and has a concave shape at both surfaces; a third lens that has the positive refractive index and has the convex shape upwards; and a fourth lens that has the negative refractive index and has a concave surface on an object-side surface, and has at least one inflection point on an image surface. It is possible to implement a compact optical system for a camera which can be applied to a mobile communication terminal by improving design flexibility.

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

Abstract: Provided are a small image pickup lens which ensures a wide angle of view, permits various aberrations to be excellently corrected and is applicable to an image pickup element having a high pixel density, an image pickup apparatus using the image pickup lens, and a mobile terminal using the image pickup apparatus. The image pickup lens employs a structure which includes, in order from the object side, an aperture stop, a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a fourth lens with negative refractive power, and the image pickup lens is designed to satisfy predetermined conditional expressions.

Abstract: The present invention is directed to an inner focusing macro lens that has a large aperture ratio as expressed by 2.5 or even smaller in F-number and still remains compact, and that is adapted to compensate for spherical aberration, astigmatism, and comatic aberration during photographing throughout the entire object distance ranging from infinity to proximity for an up to 1:1-magnification image. The inner focusing macro lens has the leading or first lens group of positive refractivity, the second lens group of negative refractivity, the third lens group of positive refractivity, and the trailing lens set succeeding to the third lens group in sequence from a position closest to an object being photographed. During focusing from a point infinitely far to that as proximal as desired, the first lens group is static while the second lens group is moved toward the imaging plane, and the third lens group is moved toward the object.

Abstract: This invention provides an optical imaging lens assembly, in order from an object side toward an image side including: a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface, a third lens element with positive refractive power having a concave object-side surface and a convex image-side surface, a fourth lens element with negative refractive power having a concave image-side surface, and the two surfaces being aspheric; wherein the optical imaging lens assembly further comprises an aperture stop disposed between an imaged object and the first lens element, and there are four lens elements with refractive power.

Abstract: There is provided an optical system configured of 4-sheet lenses to have a wide angle of view. The optical system includes: a first lens having a positive refractive power, with both surfaces being convex; a second lens having a negative refractive power, with both surfaces thereof being concave; a third lens having a positive refractive power and a meniscus shape; and a fourth lens having a negative refractive power, with both surfaces thereof being concave, all of which are disposed in order from an object to a front upper surface. In the optical system, the refractive powers of the first lens to the fourth lens satisfy the following Conditional Expression 1. f ? ? 1 f ? ? 4 < - 1.1 Conditional ? ? Expression ? ? 1 In Conditional Expression, f1: a focal distance of the first lens and f4: a focal distance of the fourth lens.

Abstract: A lens system, in order from the object, includes positive first lens, negative second lens, positive third lens, positive fourth lens, and an aperture stop positioned between the third and fourth lens. The second lens includes a first optical portion, a first support portion surrounding the first optical portion with a first surface and second surface. The third lens includes a second optical portion and a second support portion surrounding the second optical portion with a third surface and fourth surface. The fourth lens includes a light stop surface facing the object side of the lens system. The lens system satisfies the formulas: d23<1.1×d34, where the d23 is a distance along the optical axis of the lens system from the second surface to the third surface, and the d34 is a distance along the optical axis from the fourth surface to the light stop surface.

Abstract: An imaging lens includes, from an object-side to an image-side: an aperture stop, a first lens of positive refractive power with two convex surfaces along the optical axis of the imaging lens, a meniscus second lens of negative refractive power with a convex surface on the object-side, a meniscus third lens of positive refractive power with a convex surface on the image-side, a meniscus fourth lens of negative refractive power with a convex surface on the object-side. Specified conditions are satisfied in order to reduce aberrations and an Fno (focal ratio number) and enhance wide-angle view.

Abstract: An imaging lens SL installed into such as an electronic still camera 1 includes, in order from an object side: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; and a fourth lens group G4 having positive refractive power; the second lens group G2 and the third lens group G3 move along an optical axis upon focusing from infinity to a close object, and a given conditional expression is satisfied, thereby providing a fast imaging lens capable of taking a picture from infinity to a close object with high optical performance, an optical apparatus equipped with the imaging lens, and a method for manufacturing the imaging lens.

Abstract: An imaging lens includes a first lens L1 that has a biconvex shape near an optical axis and has positive refractive power, a second lens L2 that has a biconcave shape near the optical axis and has negative refractive power, a third lens L3 that has a shape of a meniscus lens directing a concave surface thereof to an object side near an optical axis and has positive refractive power, and a fourth lens L4 that has a biconcave shape near the optical axis and has negative refractive power, arranged in this order from the object side. When the whole lens system has a focal length f and the fourth lens L4 has a focal length f4, the imaging lens of the invention satisfies the following expression: ?0.7<f4/f<?0.

Abstract: An image pickup lens includes, in sequence from an object side to an image side, an aperture stop; a first lens having two convex surfaces and having a positive refractive power; a second lens in a meniscus shape whose convex surface faces to the object side having a negative refractive power; a third lens in a meniscus shape with the convex surface facing to the image side having a positive refractive power; a fourth lens in a meniscus shape with the convex surface facing to the object side having a negative refractive power. Predefined conditions are satisfied.