Abstract: A projection type image display apparatus in which shortening of the projection distance (widening of the angle of view) and miniaturization of the projection optic system are realized is provided. It comprises, in a traveling direction of the light, an image display element, a lens group including a plurality of lenses, a first lens, a second lens, and a mirror to reflect light emitted from the second lens to be projected obliquely on a screen in this order. The refractive power of the first lens is positive and the refractive power of the second lens is negative. The first and the second lenses are moved in an interlocked relationship with each other along an optical axis of the lens group and a movement amount of the first lens is made larger than a movement amount of the second lens.

Abstract: A zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming from a wide-angle limit to a telephoto limit during image taking, wherein at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing from an infinity in-focus condition to a close-object in-focus condition in at least one zooming position, and among the focusing lens units, a lens unit having the absolute value, which is not the greatest absolute value, of a wobbling value at a wide-angle limit is a wobbling lens unit which senses a moving direction of the focusing lens units at the time of focusing by wobbling itself in a direction along the optical axis; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A variable magnification optical system consists of first lens group having negative refractive power and second lens group having positive refractive power, which are in this order from an object side, and a distance in an optical axis direction between the first lens group and the second lens group changes when magnification is changed. The second lens group consists of a positive sixth lens, a negative seventh lens, a positive eighth lens, and a cemented lens composed of a negative ninth lens and a positive tenth lens cemented together, which are in this order from the object side, and all of the three positive lenses, which are the sixth lens, the eighth lens and the tenth lens, are double-convex lenses. A predetermined formula is satisfied.

Abstract: A variable magnification optical system consists of a negative first lens group, a stop that is fixed relative to an image plane during magnification change, and a positive second lens group, which are in this order from an object side. A distance between the first lens group and the second lens group in an optical axis direction becomes shorter when magnification is changed from a wide-angle end to a telephoto end. The first lens group consists of a positive lens having a convex object-side surface and two negative lenses, in this order from the object side. The variable magnification optical system satisfies the following formula (1) about Abbe number ?d1 of the positive lens in the first lens group for d-line: 25.5<?d1<50??(1).

Abstract: The objective of the present invention is to provide a zoom lens system having an f-number of approximately 1.3 at the wide extremity, a half angle-of-view of 75 degrees, and a zoom ratio of approximately 3:1. The solution to this objective is to provide a zoom lens system including a first lens group, having a negative refractive power, a diaphragm, and a second lens group, having a positive refractive power, in that order from the object side; wherein the first lens group and the second lens group move in the optical axis direction so that the distance therebetween decreases upon zooming from the wide-angle extremity to the telephoto extremity.

Abstract: A compact imaging optical system having a light-weight focusing lens is provided. The imaging optical system includes, in order from an object side to an image side, a front unit in which a negative lens element is arranged closest to the object side, an aperture diaphragm, and a rear unit having positive optical power. In focusing from an infinite distance object to a short distance object, the negative lens element arranged closest to the object side and the aperture diaphragm are fixed with respect to an image surface, and a part of lens elements included in the front unit or the rear unit moves along an optical axis. The imaging optical system satisfies the following condition (1): 0.9<R/f<2.0 (R: an average between an image side curvature radius of the negative lens element arranged closest to the object side, and an image side curvature radius of a second negative lens element from the object side among all the negative lens elements; f: a focal length of the entire system).

Abstract: A lens system comprising, in order from an object side: a first lens group G1; and a second lens group G2 having positive refractive power; the first lens group G1 including a sub-lens group GS11 having positive refractive power, and a sub-lens group GS12 having negative refractive power, the sub-lens group GS12 having negative refractive power including a meniscus lens having a convex surface facing the object side, given conditions being satisfied, thereby providing a lens system having high optical performance with excellently correcting various aberrations, and an optical apparatus equipped therewith.

Abstract: A projection lens system includes, in order from a screen-side to an SLM-side thereof, a first lens group of negative refractive power which includes a first lens, and a second lens group of positive refractive power. The second lens group includes a second to fifth lenses in order from the screen-side to the SLM-side of the projection lens system. The projection lens system satisfies the following condition formulas: 1.95<|F1/Fw|<2.15, 0.5<|f4/Fw|<0.7, and 1.05<|f5/Fw|<1.25, where F1 is the effective focal length of the first lens group, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens, Fw is the effective focal length of the projection lens system which is in the wide-angle state.

Abstract: A zooming lens including a first lens group and a second lens group arranged in sequence from an object side to an image side is provided. The first lens group has negative optical power and includes a negative concave-convex lens and a positive concave-convex lens arranged in sequence from the object side to image side. A convex surface of the negative concave-convex lens is facing toward the object side and a convex surface of the positive concave-convex lens is facing toward the object side. The second lens group has positive optical power and includes a positive convex lens, a negative biconcave lens and a positive biconvex lens arranged in sequence from the object side to image side. The first and second lens groups are movable between the object side and image side for switching the zooming lens between a wide-angle mode, a middle mode and a telephoto mode.

Abstract: A macro lens system includes a positive first lens group, and a positive or negative second lens group, in that order from the object side, wherein at least the first lens group moves toward the object side when focusing on an object at infinity to an object at a close distance, wherein the second lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side, wherein the following condition (1) is satisfied: ?5.0<f2A/fi<?0.8??(1), wherein f2A designates the focal length of the first sub-lens group, and fi designates the focal length of the entire the macro lens system when focusing on an object at infinity.

Abstract: A zoom projection lens includes a first lens set and a second lens set arranged in sequence from an object side to an image side of the zoom projection lens. The first lens set has a negative optical power. The second lens set has a positive optical power. The first lens set has a first lens. The second lens set has a second lens, a third lens, a fourth lens, and an aperture stop disposed between the second lens and the third lens. The first lens is an aspherical plastic lens. One of the third and fourth lenses is an aspherical glass lens. The zoom projection lens satisfies: 1.463<|tt/lt|<1.505, in which, tt represents an overall length of the zoom projection lens, and lt represents a length of the zoom projection lens from the object side of the first lens to an image side of the fourth lens.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. A distance between the first lens unit and the second lens unit varies during zooming. The first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens of which an object-side lens surface has a convex shape. An Abbe number of a material of the positive lens of the first lens unit, a focal length of the first lens unit, a distance between an image-side lens surface of the first lens unit and an object-side lens surface of the second lens unit at a telephoto end, and focal lengths of the entire zoom lens at a wide-angle end and the telephoto end are appropriately set.

Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

Abstract: An image forming lens consists of from an object side to an image side in the following order: a first group with a positive refractive power; an aperture stop; and a second group with a positive refractive power, wherein the second group includes, from the object side to the image side in the following order, a biconvex lens, a biconcave lens, a negative meniscus lens a convex surface of which faces the image side, a biconvex lens, and a positive meniscus lens a convex surface of which faces the image side.

Abstract: A zoom lens includes a front lens group including a first lens unit and a second lens unit, a reflecting mirror configured to bend an optical path, and a rear lens group including two or more lens units. When the zoom lens is retracted, the reflecting mirror performs at least one of rotation and linear movement to provide space for the front lens group. A focal length of a lens unit having the highest absolute value of refractive power among negative lens units in the front lens group, a focal length of the entire zoom lens at a telephoto end, a maximum value and a minimum value of amounts of movement of the at least two lens units in the rear lens group during zooming, a length of a reflecting surface of the reflecting mirror, and a maximum effective diameter of the first lens unit are appropriately set.

Abstract: An optical system includes, in order from an object side to an image side, a first lens unit of a positive refractive power, an aperture diaphragm, and a second lens unit of a positive refractive power. The first lens unit includes, in order from the object side to the image side, a cemented lens Lp1 made by joining a first lens of a positive refractive power and a second lens of a negative refractive power with each other, and a third lens of a positive refractive power which has a meniscus shape. The predetermined conditions are satisfied.

Abstract: A zoom lens system ZL mounted in an electronic still camera 1 etc is constructed to include, in order from an object side, a first lens group G1 having negative refractive power and a second lens group G2 having positive refractive power, in which the second lens group G2 has two cemented lenses. A distance between the first lens group G1 and the second lens group G2 changes when a lens position state changes from a wide-angle end state to a telephoto end state, thereby providing the zoom lens system exhibiting preferable optical performance, an optical apparatus including the zoom lens system and a magnification varying method using the zoom lens system.

Abstract: Disclosed is an image capturing lens system. The image capturing lens system includes an image capturing lens group having a plurality of lenses and a phase mask located in the image capturing lens group. The phase mask may satisfy phase mask functions that are defined with respect to x and y axes such that a modulation transfer function (MTF) of light is uniformized.

Abstract: Provided are a lens apparatus and a machine vision system including the lens apparatus. The lens apparatus includes: a first lens group and a second lens group which are designed to use a wavelength of light of a first single color as a reference wavelength and disposed on opposite sides of an aperture; and a converter lens group which is disposed at an object side of the first lens group, wherein the converter lens group performs selectively at least one of a first conversion for converting a magnification, and a second conversion for converting the reference wavelength.

Abstract: An optical device includes a first and second lens group, an operation member, a first and second lens group position detection unit, a storage unit, a control unit. The control unit controls the movement of the second lens group based on positional information of the first lens group detected by the first lens group position detection unit and the positional relationship information stored in the storage unit, and determines whether a control state of the second lens group is abnormal based on control positional information during the control of the movement of the second lens group and the signal corresponding to the position of the second lens group detected by the second lens group position detection unit.

Abstract: An optical system includes at least one lens unit having a negative refractive power disposed closer to an object side than an aperture portion. The lens unit having a negative refractive power includes at least one positive lens and one negative lens. The ratio between the numbers of positive lenses and negative lenses included in the lens unit having a negative refractive power is appropriately set. The lens unit having a negative refractive power includes a plurality of negative lenses each having an appropriate Abbe number and relative partial dispersion and a positive lens having an appropriate Abbe number. A negative lens having the highest dispersion among the negative lenses is located in an appropriate position.

Abstract: An optical system includes, in order from an object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. The optical system satisfies: 1.70?Yt/Yw?2.5, Y=2×f×sin(?/2) (85°???90°), and 3.45?bfw/|f1|?7, where fw is the shortest focal length, ft is the longest focal length, f is an arbitrary focal length that satisfies fw?f?ft, ? is an angle between the optical axis and a principal ray of an off-axis light flux incident upon a lens surface closest to the object, Y is a formed image height of a ray incident at the angle ?, Yw is the largest image height at the shortest focal length, Yt is the largest image height at the longest focal length, f1 is a focal length of the first lens unit, and bfw is a back focus at the shortest focal length.

Abstract: An optical system includes, in order from its object side a negative first lens unit, a positive second lens unit, a negative third lens unit, and a positive fourth lens unit. The air gaps between the lens units are variable during zooming. The first lens unit includes one positive lens, the second lens unit includes one negative lens, the third lens unit consists of one or two lens components, and the fourth lens unit consists of one lens component, where the term “lens component” refers to a single lens or a cemented lens. The system satisfies the condition “0<M3/M2<0.55”, where M2 and M3 are the amounts of movement of the second lens unit and the third lens unit respectively during zooming from the wide angle end to the telephoto end in the state in which the zoom lens is focused on an object point at infinity.

Abstract: To provide an image forming optical system that can achieve good correction of chromatic aberration, which is seriously needed particularly when the zoom ratio is high, while achieving slimness and a high zoom ratio and to provide an electronic image pickup apparatus equipped with such an image forming optical system, an image forming optical system has a lens group A including a lens component made up of a positive lens LA and a negative lens LB cemented together and having a negative refracting power as a whole. The lens group A is arranged between a lens group I closest to the object side and an aperture stop. The distance between the lens group I and the lens group A changes for zooming. The lens component has an aspheric cemented surface, and a certain condition concerning the shape of the aspheric surface is satisfied.

Abstract: A zoom lens system has a front lens group and a rear lens group along the optical axis and in order from the object side. The rear lens group has a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, and a third lens unit having a positive refracting power. Upon zooming from a wide-angle end state to a telephoto end state, a space between the front lens group and the first lens unit varies, a space between the first lens unit and the second lens unit increases, and a space between the second lens unit and the third lens unit decreases. At least a part of the second lens unit is movable so as to have a component in a direction perpendicular to the optical axis.

Abstract: A zoom lens comprises a first lens group having a negative refractive power and a second lens group having a positive refractive power in order from object to image sides, an interval between the first and second lens groups changes in a zoom operation, the first lens group is constituted by negative and positive lenses in order from the object to image sides, the negative and positive lenses of the first lens group are arranged at intervals, the second lens group is constituted by three lenses including positive and negative lenses in order from the object to image sides, and a radius of curvature of a lens surface at the object side of the negative lens constituting the first lens group, a shape of a negative lens having the maximum refractive power constituting the second lens group, and a refractive power of the second lens group are appropriately set.

Abstract: A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; a diaphragm; and a second lens group having a positive refractive power. Zoom from a wide angle edge to a telephoto edge is performed by displacement of the second lens group along an optical axis, toward the object side. Correction of imaging plane variation accompanying the zoom, is performed by displacement of the first lens group along the optical axis. The second lens group includes sequentially from the object side, a positive first lens having at least on aspheric surface and a positive second lens. Furthermore, a first condition ?d21>63 and a second condition ?d22>70 are satisfied, ?d21 being the Abbe number for a d-line in the first lens of the second lens group and ?d22 being the Abbe number for a d-line in the second lens of the second lens group.

Abstract: A zoom lens has a plurality of lens units including, in order from its object side to image side, a first lens unit having a negative refracting power composed of two lens elements including a biconcave negative lens and a positive lens, and a second lens unit having a positive refracting power composed of four lens elements including a positive lens and a negative lens. During zooming from the wide angle end to the telephoto end, a distance between the lens units changes, and the second lens unit moves toward the object side. The zoom lens has an aperture stop that moves integrally with the second lens during the zooming and satisfies a specific condition.

Abstract: Provided are an imaging optical system in which chromatic aberrations are excellently corrected across the entire screen to realize high optical performance, and an optical apparatus including the imaging optical system. In an imaging optical system of which a back focus is longer than a focal length, a lens unit located in a reduction-conjugate side of an aperture stop includes at least one positive lens. A partial dispersion ratio and an Abbe number of the positive lens are set such that a refractive index, a position, and a power satisfy a suitable relationship.

Abstract: An image pickup apparatus includes a zoom lens, and an image pickup element having an image pickup surface which receives optically an image formed by the zoom lens, and which converts the image received to an electric signal. The image pickup apparatus satisfies the following conditional expressions (1) Lv 1 Er/Lv 1 EL<0.49, (2) 0.93<Lv 1 Ef/IHs, and (3) Lv 1 Ef/Lv 1 Er<0.99.

Abstract: A zoom lens system ZL installed in an electronic still camera 1 and the like comprising, in order from an object side: a first lens group G1 having negative refractive power; and a second lens group G2 having positive refractive power; the second lens group including at least two cemented lenses each of which includes a positive lens disposed to the object side and a negative lens disposed to an image side, a distance between the first lens group and the second lens group varying upon zooming from a wide-angle end state to a telephoto end state, thereby providing a zoom lens system having excellent optical performance, an optical apparatus equipped with the zoom lens system, and a method for manufacturing the zoom lens system.

Abstract: A zoom lens, including: a front lens group; an aperture stop; and a rear lens group, in which the rear lens group includes: a front lens unit and a rear lens unit, a maximum air interval of the rear lens group being interposed between the front lens unit and the rear lens unit, in which the rear lens unit includes: a first lens which is located on the most object side; a second lens which is located on the most image side, and the following conditional expressions are satisfied: ?6.0?fs1/frr??1.0; and ?9.0?fs3/frr??2.0, where frr indicates a focal length of the rear lens unit, and fs1 and fs3 indicate a focal length of the first lens and a focal length of the second lens, respectively.

Abstract: A zoom lens system includes a negative first lens group and a positive second lens group, in that order from the object side, wherein upon zooming from the short focal length extremity to the long focal length extremity, the first lens group and the second lens group move in the optical axis direction while the distance therebetween mutually decreases. The first lens group includes a negative first sub-lens group and a positive second sub-lens group, in that order from the object side, wherein the second sub-lens group constitutes a focusing lens group that is moved in the optical axis direction during a focusing operation.

Abstract: A zoom lens system includes a negative first lens group, a diaphragm, and a positive second lens group. The following conditions (1) and (2) are satisfied: 5.2<(d12W?d12T)/(mT/mW)<7??(1), and 0.3<SF<0.7??(2), wherein d12W and d12T designate the distance from the surface closest to the image side of the first lens group to the surface closest to the object side of the second lens group, at the short and long focal length extremities, mT and mW designate the lateral magnification of the second lens group at the long and short focal length extremities, SF designates the shape factor of the positive lens element closest to the object side within the second lens group, and R2 and R1 designate the radius of curvature of the surface on the image side and object side, respectively, of the positive lens element closest to the object side within the second lens group.

Abstract: A zoom projection lens system includes a first lens group with negative refraction power and a second lens group with positive refraction power. The first lens group includes a first lens with negative refraction power. The second lens group includes a second lens with positive refraction power, a third lens with positive refraction power, a fourth lens with negative refraction power, and a fifth lens with positive refraction power. The zoom projection lens system satisfies the following formulas: 1.9<|F1/Fw|<2.1, 0.5<|f4/Fw|<0.8, 0.95<|f5/Fw|<1.2, where “F1”, “f4” and “f5” are respectively the effective focal lengths of the first lens group, the fourth lens and the fifth lens, “Fw” is the effective focal lengths of the zoom projection lens system in the wide angle state.

Abstract: A zoom lens includes in order from an object side to an image side and arranged along an optical axis thereof, a first lens unit having a negative refractive power, and a second lens unit having a positive refractive power. A distance between each lens unit changes when zooming from a wide-angle end to a telephoto end. The first lens unit includes a first lens sub-unit including a positive lens element and a negative lens element, and having a negative refractive power, and a second lens sub-unit including a single negative lens element. Focusing is performed by moving the second lens sub-unit in an optical axis direction, a focal length of the second lens sub-unit f1b and a focal length of the entire zoom lens fw at a wide-angle end are suitably set based on predetermined mathematical expressions.

Abstract: A variable magnification optical system includes a negative first lens group, a stop and a positive second lens group, arranged from the object side in the order mentioned above. The magnification of the variable magnification optical system is changed by changing a distance between the first lens group and the second lens group in the direction of an optical axis. The first lens group includes a negative plastic lens, and the second lens group includes a positive plastic lens. Further, the following formulas (1) and (2) are satisfied: 5.0<fpp/fw<7.5 (1); and ?7.0<fpn/fw<?6.0 (2), where fpn is the focal length of the plastic lens having negative refractive power, fpp is the focal length of the plastic lens having positive refractive power, and fw is the focal length of the entire system of the variable magnification optical system at a wide angle end.

Abstract: A photographing lens system includes a positive front lens group, an aperture diaphragm, and a positive rear lens group, in that order from the object side. The front lens group includes at least one negative lens element, and at least two positive cemented lenses, in that order from the object side, and the following conditions are satisfied: 0.35<fF/fR<1.5??(1), and ?1.4<fL1/f<?0.9??(2), wherein fF and fR designate the focal lengths of the front lens group and the rear lens group, fL1 designates the combined focal length of the negative lens elements provided within said front lens group; and f designates the focal length of the entire photographing lens system.

Abstract: An extended depth-of-field (EDOF) surveillance imaging system (8) that has a lens system (10) with a total lens power ?T and an amount of spherical aberration SA where 0.2??SA?2?. The lens system includes first lens group (G1) and a second lens group (G2). The first lens group has first and second confronting meniscus lens elements (L1, L2) that have an overall optical power ?1 such that |?1/?T|?0.05. The second lens group has a doublet (D1) and a most imagewise positive lens element (L5). An aperture stop (AS) is arranged either between the first and second lens groups or within the second lens group. An image sensor (30) is arranged to receive the image and form therefrom a digitized electronic raw image. An image processor receives and digitally filters the digitized electronic raw image to form a digitized contrast-enhanced image.

Abstract: A zoom lens system, in order from an object side to an image side, comprising: a first lens unit; and a subsequent lens unit containing at least a second lens unit, wherein an interval between the first lens unit and the subsequent lens unit varies in zooming, the zoom lens system is provided with a focusing lens unit that moves relative to an image surface in focusing from an infinity in-focus condition to a close-object in-focus condition, the focusing lens unit is an image blur compensating lens unit that moves in a direction perpendicular to an optical axis in order to optically compensate image blur, and the focusing lens unit is arranged on the image side relative to an aperture diaphragm; an imaging device; and a camera are provided.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. A distance between the first lens unit and the second lens unit varies during zooming. The first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens of which an object-side lens surface has a convex shape. An Abbe number of a material of the positive lens of the first lens unit, a focal length of the first lens unit, a distance between an image-side lens surface of the first lens unit and an object-side lens surface of the second lens unit at a telephoto end, and focal lengths of the entire zoom lens at a wide-angle end and the telephoto end are appropriately set.

Abstract: A zoom lens consisting of, in order from an object side: a first lens group G1 having negative refractive power; and a second lens group G2 having positive refractive power, the first lens group G1 including, in order from the object side, a first negative meniscus lens having a convex surface facing the object side, a negative lens, a second negative meniscus lens having a convex surface facing the object side, and a positive lens, a distance between the first lens group G1 and the second lens group G2 being varied thereby carrying out zooming, and given conditional expressions being satisfied, thereby providing a zoom lens having excellent optical performance and high resolution with being compact and lightweight, an optical apparatus, and a method for manufacturing the zoom lens.

Abstract: A video projection device includes: a video display element, a projection lens, a converter lens, and a video processing part. The video display element displays a video by an electrical video signal. The projection lens projects on a screen the video displayed on the video display element. The converter lens is attachably and detachably provided for the projection lens. The video processing part outputs different video signals to the video display element in accordance with whether or not the converter lens is attached.

Abstract: A miniature auto-focusing lens device includes a first casing, a second casing coupled to the first casing, a movable lens set disposed in the first casing, an electromagnetic driving module provided in the first casing and configured to drive the movable lens set to perform focusing and displacement, and a fixed lens set coupled to the second casing and corresponding in position to the movable lens set. The movable lens set and the fixed lens set together form an optical system of the miniature auto-focusing lens device to perform optical focusing and imaging. The fixed lens set includes a lens that outstrips any one of the lenses of the movable lens set in size.

Abstract: A zoom lens comprises a first lens group having a negative refractive power and a second lens group having a positive refractive power in order from object to image sides, an interval between the first and second lens groups changes in a zoom operation, the first lens group is constituted by negative and positive lenses in order from the object to image sides, the negative and positive lenses of the first lens group are arranged at intervals, the second lens group is constituted by three lenses including positive and negative lenses in order from the object to image sides, and a radius of curvature of a lens surface at the object side of the negative lens constituting the first lens group, a shape of a negative lens having the maximum refractive power constituting the second lens group, and a refractive power of the second lens group are appropriately set.

Abstract: A variable magnification optical system includes first-lens-group having negative refractive power, aperture stop, and second-lens-group having positive refractive power, arranged from the object-side. An aspheric lens, a central portion of the object-side surface of which is convex, is arranged on the most object-side of the second-lens-group. The object-side surface of the aspheric lens is formed in such a manner that positive power decreases from the central portion of the object-side surface of the aspheric lens toward the periphery thereof, or that an inflection point is present between the central portion and the periphery and positive power decreases as a distance from the central portion increases between the central portion and the inflection point, and negative power increases toward the periphery between the inflection point and the periphery. The aspheric surface satisfies the following formulas (1) and (2) about refractive index and Abbe number: Ne5<1.53??(1); and ?d5>75??(2).

Abstract: An image capturing device may include a detector including a plurality of sensing pixels, and an optical system adapted to project a distorted image of an object within a field of view onto the sensing pixels, wherein the optical system expands the image in a center of the field of view and compresses the image in a periphery of the field of view, wherein a first number of sensing pixels required to realize a maximal zoom magnification {circumflex over (Z)} at a minimum resolution of the image capturing device is less than a square of the maximal zoom magnification times a second number of sensing pixels required for the minimum resolution.

Abstract: The objective of the present invention is to provide a zoom lens system having an f-number of approximately 1.3 at the wide extremity, a half angle-of-view of 75 degrees, and a zoom ratio of approximately 3:1.

Abstract: A variable magnification optical system includes first lens group having negative refractive-power, an aperture-stop and second lens group having positive refractive-power, arranged from the object-side. A negative lens having a concave surface facing the image-side is arranged on the most object side of the first lens group, and an aspheric lens having a concave surface facing the object-side and an aspheric surface facing the image-side is arranged on the most image side of the first lens group. A positive lens having a convex surface facing the image-side is arranged, on the object-side of the aspheric lens, immediately before the aspheric lens. The image-side surface of the aspheric lens at the most image side of the first lens group includes a portion having higher positive power on the outside of positions through which outermost rays of an axial beam pass, compared with the vicinity of the optical axis.