Abstract: There is provided a compact zoom lens having a small lens aperture which an image from a light valve such as a DMD is projected on to a screen in an enlarged scale. There is provided a zoom lens comprising, in order from a magnifying side, a first lens group having a negative refractive power as a whole, a second lens group having a positive or negative refractive power as a whole, a third lens group having a positive refractive power as a whole and a fourth lens group having a positive refractive power as a whole, wherein a variable power as a whole lens system thereof is established by configuring such that the fourth lens group is left fixed while a variable power is effected, and the first lens group, the second lens group and the third lens group are made to move on the optical axis.

Abstract: A lens system includes, in sequence from an object side to an image side, a first lens group having negative refractive power; a second lens group having positive refractive power, which includes a composite lens with aspheric resin layers formed on object side and image side thereof, respectively; and a third lens group having positive refractive power. In zooming, the first lens group remains stationary and when performing from the wide-angle end to the telephoto end, the second lens group moves away from the image plane, while the third lens group moves toward the image plane, whereby the distance between the first and second lens groups is decreased, while the distance between the second and third lens groups is increased.

Abstract: A zoom optical system comprises a lens group 1 having one negative lens component and a lens group 2 wherein a distance on the optical axis between the lens group 1 and the lens group 2 is changed for magnification purpose. The negative lens component consists of a cemented lens of positive lens and a negative lens, and when a straight line expressed by ?gFp=?p×?dp+?p (?p=?0.00163) is set up in a rectangular coordinate system in which a horizontal axis is expressed by ?dp and an vertical axis is expressed by ?gFp, ?dp and ?gFp of the positive lens are included in domains specified by the following conditions. 0.6400<?p<0.9000 3<?dp<27 here, ? gFp is a ratio of a partial dispersion (ng?nF)/(nF?nC) of the positive lens LAP; ?dp is Abbe number (nd?1)/(nF?nC) of the positive lens LAP; nd, nC, nF, and ng are refractive indices of d,C,F and g line, respectively.

Abstract: A zoom lens system includes a first lens unit having a negative optical power and a second lens unit having a positive optical power in order from the object side to the image side. In a zooming operation, the distance between the first lens unit and the second lens unit at the telephoto end is smaller than that at the wide angle end. The first lens unit includes a single negative lens element and a single positive lens element, and materials of the lens elements are adequately set.

Abstract: An imaging device has a zoom lens system having a plurality of lens units and forming an optical image of an object so as to continuously optically zoom by varying distances between the lens unit; and an image sensor converting the optical image formed by the zoom lens system to an electric signal. The zoom lens system has from an object side: a first lens unit being overall negative and including a reflecting surface that bends a luminous flux substantially 90 degrees; and a second lens unit disposed with a variable air distance from the first lens unit, and having a negative optical power.

Abstract: A zoom lens includes a most object-side lens unit remaining fixed on the optical axis when the magnification of the zoom lens is changed and a focusing operation is performed; a most image-side lens unit remaining fixed when the focusing operation is performed; and a plurality of moving lens units lying between the most object-side lens unit and the most image-side lens unit, moved along the optical axis when the magnification is changed. The most object-side lens unit includes, in order from the object side, a negative lens component, a reflective optical component having a reflecting surface for bending the optical path, and a positive lens component. The most image-side lens unit has at least one aspherical surface. An electronic imaging device includes an electronic image sensor located on the image side of the zoom lens.

Abstract: An inverse telephoto with correction lenses comprises five lens elements with refractive power, from the object side to the image side: a first lens element with negative refractive power having a concave image-side surface; a second lens element with positive refractive power having a convex image-side surface; a third lens element with a convex object-side surface; a fourth lens element with a concave image-side surface; a fifth lens element with positive refractive power having a convex image-side surface, at least one of an object-side surface and the image-side surface of the fifth lens element being aspheric; and an aperture stop located between the first lens element and the second lens element. At least three of the surfaces of the first, second, third, fourth and fifth lens elements are aspheric.

Abstract: Providing a zoom lens system having higher optical performance, a wide, maximum angle of view of 80 degrees or more, a zoom ratio of about 2.7, and a fast aperture ratio with an f-number of about 2.8. The zoom lens system includes, in order from an object, a first lens group G1 having negative refractive power, a second lens G2 group having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power; and a fifth lens group G5 having positive refractive power. When zooming from a wide-angle end state W to a telephoto end state T, the first through fourth lens groups are moved, and the fifth lens group is fixed. Given conditional expressions are satisfied.

Abstract: Photographic wide angle zoom objective of the retrofocus type having a group of negative refractive power (VG?) comprising four lens components (L1, L2, L3, L4) and being a front group when seen from the object side, and having a rear group of positive refractive power (HG+) including six lens components (L5, L6, L7, L8, L9, L10) and facing an image plane, the distance between the rear group (HG+) and the image plane (BE) being increased, and the distance between the front group (VG?) and image plane (BE) being reduced, during an increase in the focal length, characterized in that the first two lens components (L1, L2) have a negative refractive power when seen from the object side in the light direction, the third and fourth lens components (L3, L4) are grouped into a cemented component with a positive total refractive power and the fifth lens component (L5) has a positive refractive power, the sixth and seventh lens components (L6, L7) are grouped into a cemented component with a positive total refractive p

Abstract: A zoom optical system comprising, in order from an object side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive refractive power, a space between the lens units being changed to thereby perform zooming and focusing, wherein the first lens unit is constituted of a negative lens.

Abstract: A zoom lens for projection is provided and includes a first group having a negative refractive power, a second group having a positive refractive power, a third group having a positive refractive power, and a fourth group having a positive or negative refractive power, in order from the magnification side. At variable power from a wide-angle end to a telephoto end, the second, third and fourth groups are moved to the magnification side, and the first group is slightly moved to the reduction side. Also, the following conditional expression (1) is satisfied. 0.95<frw/frt<1.05??(1) Where frw is a composite focal length of the second, third and the fourth groups at the wide-angle end, and frt is a composite focal length of the second, third group and fourth groups at the telephoto end.

Abstract: A zoom lens includes a most object-side lens unit remaining fixed on the optical axis when the magnification of the zoom lens is changed and a focusing operation is performed; a most image-side lens unit remaining fixed when the focusing operation is performed; and a plurality of moving lens units lying between the most object-side lens unit and the most image-side lens unit, moved along the optical axis when the magnification is changed. The most object-side lens unit includes, in order from the object side, a negative lens component, a reflective optical component having a reflecting surface for bending the optical path, and a positive lens component. The most image-side lens unit has at least one aspherical surface. An electronic imaging device includes an electronic image sensor located on the image side of the zoom lens.

Abstract: A zoom lens includes, in order from an object side to an image side, first, second, and third lens units having negative, positive, and positive refractive power, respectively. The zoom lens performs zooming by varying distances between the lens units. The second lens unit includes a first lens subunit composed of positive and negative lens elements, and a second lens subunit arranged on the image side of the first lens subunit and composed of positive and negative lens elements. The following conditions are satisfied: ?1n<29, ?2n<30, 18<?1p??1n<35, and 26<?2p??2n<35, where ?1p and ?1n respectively represent Abbe numbers of materials of the positive and negative lens elements of the first lens subunit, and ?2p and ?2n respectively represent Abbe numbers of materials of the positive and negative lens elements of the second lens subunit.

Abstract: At least one exemplary embodiment is directed to a zoom lens including a plurality of lens units, in which an interval between respective adjacent lens units varies during zooming, an aperture stop, and a refractive optical element made of a solid material having an Abbe number (?d) and a relative partial dispersion (?gF) satisfying the following condition: ?gF?(?1.665×10?7·?d3+5.213×10?5·?d2?5.656×10?3·?d+0.755)>0. The refractive optical element is located at a position in which distances (dw, dt) from the aperture stop to the refractive optical element on an optical axis at a wide-angle end and a telephoto end, respectively, satisfy the following condition: dt/dw>1.1.

Abstract: A three-unit zoom lens system comprising, in order from an object side, a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive or negative refractive power, wherein during magnification change from a wide-angle end to a telephoto end, a space between the first lens unit and the second lens unit narrows, the second lens unit and the third lens unit move toward the only object side, and a space between the second lens unit and the third lens unit changes during a focusing operation.

Abstract: A compact zoom lens includes a first lens group (1, 3) of negative refractive power disposed on an object side and a second lens group (2, 4) of positive refractive power disposed on an image side. Both the first and second lens groups are movable. The first and second lens groups defines a variable distance therebetween. During zooming from the wide-angle end to the telephoto end, the second lens group moves toward the object side and the variable distance between the first and second lens groups decreases. The compact zoom lens has a long back focal length with various aberrations satisfactorily corrected.

Abstract: A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group functioning as a focusing lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, the distance between the negative first lens group and the positive second lens group decreases, and the distance between the positive second lens group and the positive third lens group increases. The positive third lens group includes cemented lens elements having a positive lens element and a negative lens element. The zoom lens system satisfies the following condition: 0.2<f3?p/|f3?n|<0.35 ??(1) wherein f3?pdesignates the focal length of the positive lens element of the positive third lens group; and f3?ndesignates the focal length of the negative lens element of the positive third lens group.

Abstract: A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power. The first to third lens units are arranged in that order from an object side toward an image side, and change the distances therebetween during zooming. The following conditions are satisfied: 0.70<f2/?{square root over ((fW·fT))}<0.95, and 2.9<(?2T·?3W)/(?2W·?3T)<3.7 where fW and fT respectively represent the focal lengths of the entire zoom lens at a wide angle end and a telephoto end, f2 represents the focal length of the second lens unit, ?2W and ?2T respectively represent the imaging magnifications of the second lens unit at the wide angle end and the telephoto end, and ?3W and ?3T respectively represent the imaging magnifications of the third lens unit at the wide angle end and the telephoto end.

Abstract: A five-element 3:1 zoom lens system in which the first lens group has a negative power and includes two lens elements and the second lens group has a positive power and includes a pair of lens sub-groups, the first sub-group having a positive power and including a pair of lens elements and the second sub-group having a positive power and including a single lens element. In one embodiment the second sub-group remains stationary relative to the location of the image plane and in another embodiment the second sub-group remains stationary relative to the first sub-group while they are moved relative to the location of the image plane. Several of the lens element surfaces are aspherical. The second lens element of the first sub-group is relatively thick and has a relatively high optical power. The overall length of the lens system is relatively short.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of negative refractive power, a second lens unit of positive refractive power, and a third lens unit of positive refractive power. The first lens unit moves in a locus convex toward the image side and the second lens unit moves toward the object side during zooming from a wide-angle end to a telephoto end. The object side principal point position of the first lens unit is within the first lens unit. The movement locus of the image side principal point position of the first lens unit during zooming from the wide-angle end to the telephoto end intersects with the movement locus of the object side principal point position of the second lens unit during zooming from the wide-angle end to the telephoto end.

Abstract: There is provided a zoom lens of variable power ratio of the order of 3 in which the whole of the zoom lens is made up of three lens elements groups and the power configuration of each of the groups has an arrangement of negative, positive and negative, whereby the reduction in overall length of its optical system is enabled, so that a compact zoom lens and a camera with it can be provided. The zoom lens comprising, sequentially from an object side thereof, a first lens elements group has a negative refraction power as a whole, a second lens elements group has a positive refraction power as a whole and the third lens element group has a negative refraction power as a whole, and a variable power is realized by shifting the positions of the first and second lens elements group in the direction of an optical axis thereof.

Abstract: An electronic imaging apparatus of the present invention comprises a photographing optical system, in order from an object side, a first lens group having negative refracting power, which has a reflecting component having a reflecting surface for bending an optical path of an incident light from the object side and at least two positive lens groups arranged at an image side of the first lens group, wherein the photographing optical system is a zoom optical system and the following condition is satisfied: ?1.75<f1/fw<?0.8 where f1 is a focal length of the first lens group, and fw is a focal length at the wide angle end at the photographing optical system.

Abstract: A zoom lens, including, in order from an object side to an image side (a) a first lens unit of negative optical power, (b) a second lens unit of positive optical power, and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied to effect variation of magnification, and wherein the zoom lens satisfies the following conditions: ndp3<1.5 and ?dp3>70.0, where ndp3 and ?dp3 are a refractive index and Abbe number, respectively, of material of the positive lens in the third lens unit.

Abstract: A zoom optical system has lens groups, and performs zooming by varying distances between the respective lens groups in an optical axis direction thereof. The zoom optical system has two or more lens groups having a negative optical power and a positive optical power in this order from an object side. The first lens group (Gr1) and the second lens group (Gr2) each have three or less lens elements. The second lens group (Gr2) includes a positive lens element having a refractive index of 1.7 or more. The positive lens element has at least one aspherical surface. With this arrangement, provided are a compact and superfine zoom optical system with a zoom ratio of about two to three times, an imaging lens device incorporated with the zoom optical system, and a digital apparatus loaded with the imaging lens device.

Abstract: A zoom lens system having higher optical performance, a wide angle of view, a high zoom ratio, and compactness include, in order from an object, a first group having negative power, a second group having positive power, and a third group having positive power. At least the first and second lens groups are moved upon zooming. The first group has, in order from the object, a negative meniscus lens having a convex surface facing the object, and a positive lens. At least one surface of the negative meniscus lens is an aspherical surface. The second group has, in order from the object, a first positive lens, a second positive lens, a negative lens, and a third positive lens. At least one surface of the first positive lens is an aspherical surface. The third group has one positive lens, and at least one surface thereof is an aspherical surface.

Abstract: The invention is concerned with a small-format yet high-performance zoom optical system with a fewer lenses count, and an electronic system that incorporates it. The zoom optical system comprises, in order from its object side, a first lens unit G1 of negative refracting power, a second lens unit G2 of positive refracting power and a third lens unit G3 of negative refracting power, in which zooming is implemented by movement of at least the second lens unit G2 and the third lens unit G3, thereby varying a space between adjacent lens units. The negative first lens unit G1 is composed of one negative lens, the positive second lens unit G2 is composed of one positive lens, and the negative third lens unit G3 is composed of one negative lens. The negative lens in the third lens unit G3 is in a negative meniscus shape with a concave surface on its image plane side.

Abstract: A wide-angle zoom lens system includes a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, a distance between the negative first lens group and the positive second lens group decreases, a distance between the positive second lens group and the negative third lens group increases, and a distance between the negative third lens group and the positive fourth lens group decreases. The wide-angle zoom lens system satisfies the following conditions: 0.9<f2/ft<1.2??(1) 2.9<f4/fw<3.4??(2) wherein f2: the focal length of the positive second lens group; f4: the focal length of the positive fourth lens group; ft: the focal length of the entire wide-angle zoom lens system at the long focal length extremity; and fw: the focal length of the entire wide-angle zoom lens system at the short focal length extremity.

Abstract: An exemplary zoom lens for use in projection technology includes, in this order from the magnification side to the minification side thereof, a first lens group having negative refraction of power, a second lens group having positive refraction of power, a third lens group having positive refraction of power, a fourth lens group having negative refraction of power, and a fifth lens group having positive refraction of power, wherein the zoom lens satisfies the formulas: ?1.5<F1/Fw<?1.3, 1.5<F2/Fw<1.8, 1.8<F3/Fw<2.2, ?10<F4/Fw<?5, and 2.3<F5/Fw<2.8, where F1, F2, F3, F4, F5, and Fw respectively represent the effective focal length of the first lens groups, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the shortest effective focal length of the zoom lens.

Abstract: The two-group zoom lens comprises in order from the object side, the first negative lens group, and the second positive lens group. Change of magnification from a wide angle end to a telephoto end is performed by narrowing the interval between two lens groups, and the first negative lens group is moved toward the object side when focusing from focusing at the infinite object point to focusing at a short-distance object point performed, and specific conditions are satisfied.

Abstract: The zoom lens includes a plurality of lens units. The first lens unit is disposed closest to a magnification side in the plurality of lens units and has a negative optical power, and magnification-varying lens units that are disposed closer to a reduction side than the first lens unit and moves for variation of magnification. The first lens unit includes, in order from the magnification side, a first-A lens sub-unit having a negative optical power and a first-B lens sub-unit having a positive optical power. For focusing from an infinite side to a close side, the first-A and first-B lens sub-units move as a distance therebetween increases, and the first-B lens sub-unit moves toward the reduction side. The zoom lens is capable of correcting well variation of curvature of field due to a projection distance change and has a good optical performance.

Abstract: An image projection optical system introduces light from an image-forming element by a zoom lens via an optical element. The optical element satisfies ?(Di×Ndi)/fw>4.0. The zoom lens includes, in order from a magnification side, first and second lens units, and lens units disposed closer to a reduction side than the second lens unit. The first lens unit is a negative lens unit. The lens units disposed closer to the reduction side than the second lens unit satisfy |dn/dt|<1.0×10?5. Magnification-side positive lens elements disposed closer to the magnification side than a negative lens element whose effective diameter is smallest in the lens units disposed closer to the reduction side than the second lens unit satisfy {9.0×?(1/fpA)+5.0×?(1/fpB)+0.5×?(1/fpC)}/?(1/fp)<1. Reduction-side positive lens elements disposed closer to the reduction side than the negative lens element whose effective diameter is smallest satisfy {9.0×?(1/fpA)+0.3×?(1/fpB)+2.0×?(1/fpC)}/?(1/fp)<1.

Abstract: At least one exemplary embodiment is directed to a zoom lens comprising a plurality of lens units, where the plurality of lens units have at least one negative lens including a first negative lens Gn1 arranged at a position where an effective diameter is minimized among negative lenses of the zoom lens, where when the at least one negative lens is represented by an ith negative lens Gni indicating the ith negative lens from an expansion side toward the reduction side and Xi=?gFni?(0.6438?0.001682×?dni), the following condition is satisfied: (?Xi×fni)/(?fni)<?0.003, where the Abbe number and the partial dispersion ratio of the material of the ith negative lens Gni are ?dni and ?gFni, respectively, and the focal length of the ith negative lens Gni is fni.

Abstract: In a thin projector for projecting an image from a light valve such as a DMD, a compact zoom lens comprises, in order, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens-group having a negative refractive power, and a fourth lens group having a positive refractive power. The fourth lens group is fixed while the focal length is being changed. The first and second lens group are movable on an optical axis in a direction from the enlarging side towards the reducing side over a range from a wide angle end to an intermediate range, and are movable on the optical axis in a direction from the reducing side towards the enlarging side over a range from the intermediate range to a telephoto end. The third lens group moves on the optical axis in a direction from the reducing side to the enlarging side over a range from the wide angle end to the telephoto end, whereby the focal length of the whole lens system of the zoom lens is changed.

Abstract: A zoom lens comprises a plurality of lens units including a first lens unit disposed most adjacent to an enlargement side and having negative refractive power, wherein one or more lens units of the plurality of lens units are moved in the direction of the optical axis thereof during magnification change, and wherein the first lens unit includes a 1-1st lens unit comprising at least one lens of negative refractive power and moved during focusing and a 1-2nd lens unit having positive refractive power, and fixed during focusing.

Abstract: A zoom lens of the invention has three lens groups. In the zoom lens, magnification change is performed by moving only one lens group among the three lens groups, and focus adjustments is performed by moving one of a first lens group and a second lens group counted from an enlargement conjugate side among the three lens groups. In addition, the zoom lens is approximately telecentric on reduction conjugate side thereof.

Abstract: A zoom lens includes a first lens group having positive or negative refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. A variable power is set such that the first and fourth lens group are left fixed, the second lens group is made to move from a magnifying side to a contracting side over a range from a wide angle end to an intermediate area and is made to move on an optical axis from the contracting side to the magnifying side over a range from the intermediate area to a telephoto end, and the third lens group is made to move on the optical axis from the contracting side to the magnifying side over a range from the wide angle end to the telephoto end.

Abstract: First, second, third and fourth lens groups of a zoom lens portion are arranged on an optical axis in order from an object to be imaged side toward an electronic imaging device. The first lens group has a negative refracting power and a fixed position on the optical axis. The second lens group has a positive refracting power and is moved along the optical axis to effect focusing. The third lens group has a positive refracting power and is moved along the optical axis during a magnification change. The fourth lens group has a fixed position on the optical axis. An angle of incidence of a ray of a maximum image height when the zoom lens portion is in a state at a telephoto end is not greater than the angle of incidence of the ray of the maximum image height incident on the electronic imaging device when the zoom lens portion is in a state at a wide angle end.

Abstract: The invention provides a zoom lens system suitable for an image gathering system using a solid-state imaging device, having a zoom ratio of about three, a small lens length, and superb optical performance. The zoom lens system includes, in order from an object, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. The first lens group consists only of a negative lens and a positive lens. The second lens group includes at least two positive lenses and at least one negative lens. The third lens group consists of one lens. Zooming from a wide-angle end state to a telephoto end state is conducted by decreasing a distance between the first and second lens groups, increasing a distance between the second and third lens groups, and fixing the third lens group. Given conditions are satisfied.

Abstract: At least one exemplary embodiment is directed to a zoom lens system which includes a first lens unit having negative refractive power and a second lens unit having positive refractive power. The first and second lens units are provided in order from the object to image sides. The distance between the first and second lens units change during zooming. The first lens unit includes a compound optical element including a lens element and a resin layer having optical performance different from that of the lens element and being stacked on the lens element. The zoom lens system can satisfy: 20<|?dg??dj| and fg/fj<0, where fg and ?dg represent the focal length and the Abbe number of the lens element and fj and ?dj represent the focal length and the Abbe number of the resin layer.

Abstract: An object of the present invention is to provide a compact size variable power optical system capable of producing a high quality image. The variable power optical system comprises a plurality of lens groups for forming an optical image on an image surface of an image pickup device. Among the plurality of lens groups, the first lens group, which is disposed in the most subject side has a negative refraction power, includes at least a lens having a negative refraction power and a reflective optical element for bending the optical axis. When varying the variable power, the axial distance between the first lens group and the image surface varies. When Nd denotes the refraction power of the lens having negative refraction power at d-line, the refraction power satisfies the conditional formula Nd>1.81.

Abstract: A compact zoom lens includes, in order from an object side to an image side, a first lens group (1) of negative refractive power, and second, third, fourth and fifth lens groups (2, 3, 4, 5) of positive refractive power. The second, third and fourth lens groups are movable to effect zooming and focusing. During zooming from the telephoto end to the wide-angle end, the fourth lens group moves from the object side to the image side. The compact zoom lens has a long back focal length with various aberrations satisfactorily corrected, and a small F-number for enhanced image brightness.

Abstract: Providing a compact zoom lens system with high optical performance suitable for an SLR digital camera with a solid-state imaging device of the APS-C size. The zoom lens system includes, in order from an object, a first group having negative power, a second group having positive power, a third group having negative power, and a fourth group having positive power. Upon zooming from a wide-angle end state to a telephoto end state, the second, third and fourth groups are moved to the object such that a distance between the first and second groups decreases, a distance between the second and third groups increases, and a distance between the third and fourth groups decreases. Each of the first, second and fourth groups is composed of at least one positive lens and at least one negative lens. The third group consists of a single lens. Given conditional expressions are satisfied.

Abstract: An imaging optical system which is a small-sized and wide angle of view a zoom lens, and whose aberration is finely corrected, is provided. In the imaging optical system, it has the first lens group of negative power, the second lens group of positive power, the third lens group of negative power, the fourth lens group of the positive and the following lens group, and the first lens group is fixed with respect to the image plane during zooming and focusing, and during zooming at least the lens group constituting the following lens group is moved within an adequate range, and the distance between the most image side surface of the following lens group and the image plane is set in an adequate range.

Abstract: A compact zoom lens suitable for an imaging optical system using a solid-state image sensing device is provided. The zoom lens includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. The first through third lens groups are sequentially arranged from an object side toward an image side. The first, second, and third lens groups move when magnification changes from the wide-angle position to the telephoto position, and a refractive index G1n of at least one lens element included in the first lens group satisfies 1.90<G1n<2.00.

Abstract: A zoom lens includes, in sequence from the object side: a first lens group with an overall negative refractive power; and a second lens group with an overall positive refractive power. A zoom factor changes by moving the second lens group. Focal adjustments are made by moving the first lens group accompanied by the change of the zoom factor made by the movement of the second lens group. The first lens group includes a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens group includes a third lens having a positive refractive power, a fourth lens with a positive refractive power and a fifth lens with a negative refractive power bonded together, and a sixth lens with a positive refractive power. The bonded lenses form a meniscus shape with a convex surface facing the object side. The resulting lens is short in length, compact, thin, and suitable for digital still cameras.

Abstract: Providing a two-lens-group zoom lens system that has a wide angle of view, a fast aperture ratio with an f-number of about 2.8, a high zoom ratio, and high optical performance, and is easy to be manufactured. The zoom lens system is composed of, in order from an object, a first lens group G1 having negative refractive power, and a second lens group G2 having positive refractive power. Zooming is carried out by varying a distance between the first lens group G1 and the second lens group G2. The second lens group G2 includes, in order from the object, a first positive lens component L1, an aperture stop S, a second positive lens component L2, and a negative lens L3. Given conditional expression is satisfied.

Abstract: Photographic wide angle zoom objective of the retrofocus type having a group of negative refractive power (VG?) comprising four lens components (L1, L2, L3, L4) and being a front group when seen from the object side, and having a rear group of positive refractive power (HG+) including six lens components (L5, L6, L7, L8, L9, L10) and facing an image plane, the distance between the rear group (HG+) and the image plane (BE) being increased, and the distance between the front group (VG?) and image plane (BE) being reduced, during an increase in the focal length, characterized in that the first two lens components (L1, L2) have a negative refractive power when seen from the object side in the light direction, the third and fourth lens components (L3, L4) are grouped into a cemented component with a positive total refractive power and the fifth lens component (L5) has a positive refractive power, the sixth and seventh lens components (L6, L7) are grouped into a cemented component with a positive total refractive p

Abstract: An electronic imaging apparatus includes a zoom optical system having, in order from the object side, a first lens unit with negative power and a second lens unit with positive power, in which lens components having refracting power in the first lens unit are only a single biconcave negative lens element located at the most object-side position and a positive lens component located at the most image-side position; an electronic image sensor placed on the image side of the zoom optical system; and an image processing section electrically processing image data obtained by the electronic image sensor to change the shape thereof. The zoom lens system satisfies the following conditions in focusing of a nearly infinite object point: 0.85<|y07/(fw·tan ?07w)|<0.97 0.75<|y10/(fw·tan ?10w)|<0.

Abstract: A zoom lens system has a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power in order to from an object side, spaces between the respective lens units change during zooming, and the zoom lens system satisfies predetermined conditions.

Abstract: At least one exemplary embodiment is directed to a zoom lens which includes, in order from an object side to an image side, a first lens unit with a negative refractive power, a second lens unit with a positive refractive power, and a third lens unit with a negative refractive power. The second and third lens units move during zooming. The first lens unit includes a negative biconcave lens element. The zoom lens satisfies the following conditions: ?1.4<?1/?w<?1.0 0.9<?2/?w<1.4 ?1.3<?3/?w<?0.9 where ?1 is a refractive power of the first lens unit, ?2 is a refractive power of the second lens unit, ?3 is a refractive power of the third lens unit, and ?w is a refractive power of the entire system at a wide-angle end.