Abstract: An imaging lens for an image pickup device is formed of only three lens components of positive, negative, and positive refractive power, in order from the object side. A diaphragm stop is positioned on the object side of the lens component nearest the object side. Six lens component lens surfaces are aspheric. The lens component nearest the object side is biconvex with regard to the central areas of its two lens surfaces. The image-side surface of the lens component nearest the image side has a concave central area surrounded by a convex surface area. The middle lens component has one lens surface with a concave central area and one lens surface with a convex central area. The Abbe number of the central lens element and the ratio of the focal length of the imaging lens divided by the focal length of the object-side lens component satisfy specified conditions.

Abstract: A zoom lens includes three lens groups. The first lens group from the object side has negative refractive power and is formed of two lens components. The second lens group from the object side has positive refractive power and is formed of two lens components. The third lens group is formed of one lens component and has positive refractive power. All but one of the lens components may be lens elements. Only the first and second lens groups move along the optical axis for zooming. At least one lens surface of the second lens group has portions with curvatures of different signs. The zoom lens may include as many as five other aspheric surfaces. The aspheric lenses are made of plastic. The zoom lens may be formed of only the three lens groups and satisfies specified conditions to assure that the zoom lens is compact and favorably corrects various aberrations.

Abstract: An imaging lens having a two-group, two-lens-element construction is disclosed that is formed of, in order from the object side without any intervening lens elements: an aperture stop; a first lens element of positive refractive power with its surface on the object side being aspherical and convex near the optical axis and its surface on the image side being aspherical and either convex or concave near the optical axis; and a second lens element of positive refractive power with its surface on the object side being aspherical and convex near the optical axis and its surface on the image side being aspherical and concave near the optical axis but convex toward the periphery. Specified conditions are satisfied in order to reduce various aberrations and provide a sufficient back focus for the insertion of other optical elements.

Abstract: An imaging lens includes, in order from the object side: a first lens component of negative refractive power with two aspheric surfaces including a concave surface near the optical axis on the image-side; a second lens component of positive refractive power with a convex surface on the object side; a third lens component having positive refractive power and including lens elements having positive and negative refractive powers; and a fourth lens component having an aspheric surface on the image side that is convex near the optical axis and is concave at the periphery. The imaging lens satisfies a specified condition to assure a sufficient back focus for insertion of additional optical elements, a sufficiently small imaging lens diameter, and favorable correction of aberrations. The imaging lens has a wide picture angle, consists of only 5 lens elements in the disclosed embodiments, and is particularly suited for a text imaging camera.

Abstract: An imaging lens includes, in order from the object side, a positive meniscus first lens component with its convex lens surface on the object side, a positive meniscus second lens component with its convex lens surface on the image side, and a negative third lens component with its concave lens surface on the image side. At least both lens surfaces of the negative third component are aspheric, and all six lens surfaces of the three lens components may be aspheric. The negative refractive power of the third lens component gradually decreases from the center of the third lens component toward the periphery of said third lens component and the peripheral region of the third lens component, outside 70% of its radius, has positive refractive power. The imaging lens may consist of only three lens components or elements. A diaphragm is positioned between the first and second lens components.

Abstract: An imaging lens having a two-group, two-lens-element construction is disclosed that is formed of, in order from the object side without any intervening lens elements: an aperture stop; a first lens element of positive refractive power with its surface on the object side being aspherical and convex near the optical axis and its surface on the image side being aspherical and either convex or concave near the optical axis; and a second lens element of positive refractive power with its surface on the object side being aspherical and convex near the optical axis and its surface on the image side being aspherical and concave near the optical axis but convex toward the periphery. Specified conditions are satisfied in order to reduce various aberrations and provide a sufficient back focus for the insertion of other optical elements.

Abstract: An imaging lens for an image pickup device is formed of only three lens components of positive, negative, and positive refractive power, in order from the object side. A diaphragm stop is positioned on the object side of the lens component nearest the object side. Six lens component lens surfaces are aspheric. The lens component nearest the object side is biconvex with regard to the central areas of its two lens surfaces. The image-side surface of the lens component nearest the image side has a concave central area surrounded by a convex surface area. The middle lens component has one lens surface with a concave central area and one lens surface with a convex central area. The Abbe number of the central lens element and the ratio of the focal length of the imaging lens divided by the focal length of the object-side lens component satisfy specified conditions.

Abstract: Provided is a close-up attachment lens suitably applicable to a taking lens body comprising a lens group in charge of a focus function and a lens group in charge of a zoom function completely separate from each other. The attachment lens is mounted on the taking lens body on an object side for close-up shooting. The attachment lens comprises a cemented lens having a negative refractive power as a whole, the cemented lens including a first lens with a convex surface on an object side having a positive refractive power and a second lens with a convex surface on an image plane having a negative refractive power, and a third single lens having a positive refractive power. The taking lens body comprises a focus lens group, a zoom lens group and a master lens group which are disposed independently of one another. The use of the attachment lens allows close-up shooting while maintaining various aberrations in a taking lens in a favorable condition.

Abstract: A compact photographic lens for a digital camera is disclosed. The photographic lens has only two lens elements, yet provides excellent imaging even at the periphery of the image field. The photographic lens of the invention and an image sensor, together, fit within a volume of about 10 cm3. The lens is formed of, in order from the object side, a biconvex lens element having two aspherical surfaces, and a positive meniscus lens element having two aspherical surfaces. The convex surface of the meniscus lens element is positioned on the image side, and various conditions are satisfied in order to provide the photographic lens with a short overall length while favorably correcting various aberrations.

Abstract: An imaging lens includes, in order from the object side, a positive meniscus first lens component with its convex lens surface on the object side, a positive meniscus second lens component with its convex lens surface on the image side, and a negative third lens component with its concave lens surface on the image side. At least both lens surfaces of the negative third component are aspheric, and all six lens surfaces of the three lens components may be aspheric. The negative refractive power of the third lens component gradually decreases from the center of the third lens component toward the periphery of said third lens component and the peripheral region of the third lens component, outside 70% of its radius, has positive refractive power. The imaging lens may consist of only three lens components or elements. A diaphragm is positioned between the first and second lens components.

Abstract: An imaging lens, is formed of, in order from the object side, a zoom section for focusing and zooming, and a master section for imaging and vibration control. The master section is formed of, in order from the object side, a front lens group, and a rear lens group. The front lens group is afocal so that collimated light enters the rear lens group. The rear lens group includes, in order from the object side, a lens subgroup which is movable normal to the optical axis of the imaging lens for vibration control, and a lens subgroup for macro-imaging adjustment and tracking adjustment, which is movable along the optical axis. Preferably, a fixed lens subgroup is positioned between the lens subgroup for vibration control and the lens subgroup for macro-imaging adjustment and tracking adjustment.

Abstract: A compact photographic lens for a digital camera is disclosed. The photographic lens has only two lens elements, yet provides excellent imaging even at the periphery of the image field. The photographic lens of the invention and an image sensor, together, fit within a volume of about 10 cm3 The lens is formed of, in order from the object side, a biconvex lens element having two aspherical surfaces, and a positive meniscus lens element having two aspherical surfaces. The convex surface of the meniscus lens element is positioned on the image side, and various conditions are satisfied in order to provide the photographic lens with a short overall length while favorably correcting various aberrations.

Abstract: An imaging lens, is formed of, in order from the object side, a zoom section for focusing and zooming, and a master section for imaging and vibration control. The master section is formed of, in order from the object side, a front lens group, and a rear lens group. The front lens group is afocal so that collimated light enters the rear lens group. The rear lens group includes, in order from the object side, a lens subgroup which is movable normal to the optical axis of the imaging lens for vibration control, and a lens subgroup for macro-imaging adjustment and tracking adjustment, which is movable along the optical axis. Preferably, a fixed lens subgroup is positioned between the lens subgroup for vibration control and the lens subgroup for macro-imaging adjustment and tracking adjustment.

Abstract: An image-capturing lens is formed of front and rear lens groups having negative and positive refractive power, respectively, in order from the object side. The rear lens group is formed of, in relative sequential order from the most object side of the rear lens group, a biconvex lens element that is cemented to a biconcave lens element, a biconvex lens element, and a biconvex lens element. A specified condition is satisfied so as to make the cemented lens of the rear lens group insensitive to de-centering errors which may occur either in making the cemented lens or in assembling the image-capturing lens.

Abstract: An image-capturing lens is formed of front and rear lens groups having negative and positive refractive power, respectively, in order from the object side. The rear lens group is formed of, in relative sequential order from the most object side of the rear lens group, a biconvex lens element that is cemented to a biconcave lens element, a biconvex lens element, and a biconvex lens element. A specified condition is satisfied so as to make the cemented lens of the rear lens group insensitive to de-centering errors which may occur either in making the cemented lens or in assembling the image-capturing lens.

Abstract: Provided is a close-up attachment lens suitably applicable to a taking lens body comprising a lens group in charge of a focus function and a lens group in charge of a zoom function completely separate from each other. The attachment lens is mounted on the taking lens body on an object side for close-up shooting. The attachment lens comprises a cemented lens having a negative refractive power as a whole, the cemented lens including a first lens with a convex surface on an object side having a positive refractive power and a second lens with a convex surface on an image plane having a negative refractive power, and a third single lens having a positive refractive power. The taking lens body comprises a focus lens group, a zoom lens group and a master lens group which are disposed independently of one another. The use of the attachment lens allows close-up shooting while maintaining various aberrations in a taking lens in a favorable condition.

Abstract: A simple-structured zoom lens having four lens groups is disclosed wherein the zoom lens does not require refocusing after a zooming operation even when the wavelength of light being imaged is different from the design wavelength. The zoom lens includes, in order from the object side, a first lens group which has positive refractive power; a second lens group which has negative refractive power and is moved along an optical axis to accomplish zooming, a third lens group, and a fourth lens group having at least a portion thereof which is moveable along the optical axis during zooming, wherein an image surface is made to form at the same position as for a particular design wavelength when said zoom lens is used to image light at a different wavelength by moving said portion a specified distance in accordance with the wavelength of the incident light and the zoom ratio.