Abstract: A zoom lens includes a first lens group and a second lens group disposed between the first lens group and an image side. The first lens group has three lenses. Refractive powers of the three lenses arranged from an object side to the image side are respectively negative, negative, and positive. The second lens group has five lenses. Refractive powers of the five lenses arranged from the object side to the image side are respectively positive, negative, positive, negative, and positive. Effective focal lengths (EFL) of the first and the second groups are respectively f1 and f2. The EFL of the zoom lens is fw when the zoom lens is switched to a wide end. The zoom lens satisfies ?2.8<f1/fw<?2.5 and 0.75<|f1/f2|<0.9.

Abstract: An exemplary lens includes an optical axis, an optically active part, and an optically inactive part surrounding the optically active part. The optically inactive part includes a base and a peripheral sidewall extending in a direction parallel to the optical axis. The base is connected with the active part. The side wall is a hollow cylinder. The sidewall has an internal thread formed on an internal surface thereof.

Abstract: An image pickup optical system includes a first-lens unit having negative refractive power; a second-lens unit having positive refractive power and being disposed closer to an image side than the first-lens unit; an aperture; and a diffraction optical part provided on the joint surface of a first-cemented lens closer to the image side than the aperture. The focal length of the whole system, the Abbe number of the negative lens of a second-cemented lens closer to the image side than the aperture, the focal length within the air, the Abbe number of a negative lens closer to an object side than the aperture, the average value between the curvature radius closest to the object side and the curvature radius closest to the image side of the first-cemented lens including the diffraction optical part, the curvature radius of the diffraction optical part, and so forth, are set appropriately.

Abstract: A two-group zoom projection lens is provided and includes: in order from a magnification side, a first lens group having a negative refractive power; and a second lens group having a positive refractive power, the second lens group including a front group and a rear group in order from the magnification side, the front group including a group having at least two positive lenses and a group having at least one negative lens in order from the magnification side, the rear group including a group having at least one negative lenses and a group having at least two positive lenses in order from the magnification side. The front group includes a negative lens having a concave surface directed toward the magnification side, the rear group includes a negative lens having a concave surface directed toward a reduction side, and the projection lens satisfies conditional expressions specified in the specification.

Abstract: A configuration where a first group having a positive refractive power and a positive second group having a positive refractive power are placed sequentially from the object side is basically used. As the first group, a wide-angle first group and a telephoto first group are selectively switched over to be placed on the optical axis, thereby switching over the focal length between the wide-angle side and the telephoto side. Since the configuration in which the first group placed on the object side is switched is employed, adherence of dust or the like to the imaging surface due to the switching of the focal length can be prevented from occurring. Each group is configured by a minimum number of lenses. The whole system has a configuration which has a reduced number of lenses, and which is small and simple.

Abstract: A zoom lens assembly and zoom lens module are provided, including a first lens, a second lens, a plurality of guiding blocks, a sheathing tube, a plurality of linking members and an adjusting tube. The first lens includes a plurality of curved surfaces disposed on a second lens surface toward a first lens surface. The second lens includes a plurality of driving rods disposed on a third lens surface and abutting the curved surfaces. The guiding blocks are respectively fixed on the first lens. The sheathing tube sheathes the first lens and the second lens and comprises a plurality of guiding notches to receive the guiding blocks, and a plurality of slits. The linking members pass through the slits and are fixed on the second lens. The adjusting tube sheathes the sheathing tube and comprises a plurality of driving notches to receive the linking members.

Abstract: A zoom lens includes a first lens unit having a negative refractive power and a second lens unit having a positive refractive power, which are arranged in order from the object side to the image side. The zoom lens performs zooming by changing a distance between the lens units. The first lens unit includes a compound optical element including a lens element and a resin layer having optical characteristics different from optical characteristics of the lens element, the resin layer being laminated on the lens element. An Abbe number ?dg of a material of the lens element, an Abbe number ?dj of a material of the resin layer, and an anomalous partial dispersion ratio ??gFj of the material of the resin layer are adequately set.

Abstract: An optical accessory having a high optical performance arranged to change an optical characteristic of a shooting lens and to be attached on the object side of a shooting lens is provided. The optical accessory FE is to be detachably attached to the object side of a master lens M and has at least one lens FE having a negative refractive power. The image-side surface r2 of the lens FE is designed to have an aspherical shape having a negative refractive power that decreases toward its periphery.

Abstract: Providing a zoom lens system excellently correcting various aberrations with accomplishing to be compact, lightweight, and slim upon being accommodated, and to provide an optical apparatus using the zoom lens system. The system consists of, in order from an object, a first group G1 having negative power, a second group G2 having positive power. Upon zooming from a wide-angle end W to a telephoto end T, a distance between the first group G1 and the second group G2 decreases. The first group G1 consists of, in order from the object, a first lens L1 having negative power and a second lens L2 having positive power. The second group G2 consists of, in order from the object, a third lens L3 having positive power, a fourth lens L4 having negative power, and a fifth lens L5 having positive power. Given conditions are satisfied.

Abstract: A zoom lens includes, sequentially from an object side, a first lens group having a negative refractive power; and a second lens group having a positive refractive power, where focal length is varied by changing a distance between the first lens group and the second lens group, and a first conditional expression 0.8<|f1/f2|<1.0 is satisfied, f1 being the focal length of the first lens group and f2 being the focal length of the second lens group.

Abstract: A zoom lens includes a first and a second lens group respectively having negative and positive refractive power, and changes a focal length by changing a distance between the first and the second lens group. The second lens group includes a first lens having positive refractive power and a convex surface, a second lens having positive refractive power, an aspheric surface, and a convex surface, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens including one lens or more having positive refractive power. The third and the fourth lenses are connected, and the zoom lens satisfies Nd21>1.8 and ?d24>80, where Nd21 is a refractive index of the first lens of the second lens group at a d-line, and ?d24 is an Abbe number of the fourth lens of the second lens group at a d-line.

Abstract: A zoom lens including a first lens group with a negative refractive power and a second lens group with a positive refractive power is provided. The first lens group includes a first lens, a second lens, and a third lens arranged from an object side to an image side in sequence. The refractive powers of the first, second, and third lenses are negative, negative, and positive sequentially. The second lens group includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged from the object side to the image side in sequence. The refractive powers of the fourth, fifth, sixth, and seventh lenses are positive, positive, negative, and positive sequentially. The first lens group and the second lens group are capable of moving between the object side and the image side.

Abstract: The variable-power optical system is provided and includes a first lens group having a negative refractive power, a stop, and a second lens group having a positive refractive power, in order from an object side. The first lens group includes a first sub lens group having three negative meniscus lenses and a second sub lens group having a biconcave lens and a positive lens, in order from the object side. The second lens group includes a first positive lens arranged closest to the object side and having at least one aspheric surface and a second positive lens arranged immediately after the image side of the first positive lens. When the absolute value of the focal length of the first lens group is |f1| and the focal length of the entire system at a wide angle end is fw, the Conditional expression: 1.9<|f1|/fw<3.6 is satisfied.

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

Abstract: A zoom lens includes, from the object side, first and second lens units of negative and positive refractive power. The lens units move during zooming from the wide-angle end to the telephoto end. The first lens unit includes, from the object side, three negative lenses and a positive lens, at least one of the surfaces of these lenses being aspherical. A spherical surface whose center of curvature is on the optical axis and that includes a point of the intersection of a lens surface and the optical axis and a point on the lens surface determined by the effective aperture is referred to as reference spherical surface of the lens surface. In the first lens unit, the radiuses of curvature of the image-side reference spherical surface of the most object-side negative lens and the object-side reference spherical surface of the second most object-side negative lens are appropriately set.

Abstract: A zoom lens system comprising, in order from an object side: a first lens unit comprising two lens components; and a second lens unit comprising one lens component, during zooming, a space between the first lens unit and the second lens unit changing, the first lens unit and the second lens unit having aspherical surfaces, at least one aspherical surface of the first lens unit satisfying the following condition: R1/hl 1.35, wherein R1 denotes a paraxial radius of curvature of the at least one aspherical surface, and hi denotes a length from a first intersection between a chief ray reaching a point of maximum image height on an image surface and the at least one aspherical surface to an optical axis in the wide-angle end at a time when the chief ray enters the zoom lens system with an angle of incidence equal to or larger than 36 degrees.

Abstract: A zoom lens includes, in order from the object side thereof, a first lens unit G1 having a negative refracting power and a second lens unit G2 having a positive refracting power. During zooming from the wide angle end to the telephoto end, the distance between the first lens unit G1 and the second lens unit G2 decreases. Letting the term “lens component” refer to a lens member whose surfaces that are in contact with air on the optical axis include only two surfaces, one being an object side surface and the other being an image side surface, the first lens unit G1 is comprised of a negative lens component in the form of a cemented lens having a negative refracting power that has, in order from the object side, a negative lens having a concave surface directed toward the image side and a positive lens having a convex surface directed toward the object side, and the second lens unit G2 includes a lens component in the form of a cemented lens having at least one negative lens and a positive lens.

Abstract: To provide a compact, high-performance zoom lens having a small lens aperture for enlarging an image from a light valve such as a DMD for forming an image by changing a reflecting direction of light and projecting the image so enlarged on to a screen or the like, the zoom lens includes, in order from a magnifying side, a first lens group having a negative refractive power as a whole and a second lens group having a positive refractive power as a whole, wherein changing the magnification of a whole lens system thereof is attained by configuring such that while a magnification varying operation is in effect, the first lens group and the second lens group are made to move on the optical axis.

Abstract: An imaging apparatus, configured to form an image on an image pickup element, includes, in an order from an object side toward an image side, a first optical unit having a negative refractive power, a second optical unit having a positive refractive power, and a third optical unit including the image pickup element. The first optical unit does not move during zooming. The second optical unit moves toward the object side and the third optical unit moves.

Abstract: In an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the negative lens group is disposed at an image side of the of the aperture stop, the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1), and a line when an upper limit value is in a range of the following conditional expression (1), and an area determined by following conditional expressions (2) and (3). 1.45<??2.15??(1) 1.30<Nd<2.20??(2) 3<?d<12??(3) Here, Nd denotes a refractive index, and ?d denotes an Abbe's number.

Abstract: An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the negative lens group is disposed at an object side of the aperture stop, the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a). 1.45<?<2.15??(1a) 1.30<Nd<2.

Abstract: An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an image-plane side of the aperture stop, the positive lens group has a cemented lens which is formed by cementing a plurality of lenses, in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1), and a line when an upper limit value is in a range of the following conditional expression (1), and in an area determined by following conditional expressions (2) and (3) 1.45<??2.15??(1) 1.30<Nd<2.

Abstract: A lens system includes, in order from an object: a first lens group having negative refractive power; and a second lens group having positive refractive power, the first lens group including, in order from the object, a lens having a negative refractive power, a plastic aspherical lens, and a lens having a positive refractive power, and the following conditional expression |fp/f1|>4.0 being satisfied, where fp denotes a focal length of the plastic aspherical lens, and f1 denotes a focal length of the first lens group.

Abstract: A projection apparatus includes a distance measuring unit that measures a distance to a screen on which an image is to be projected; a projection unit that has a zoom mechanism unit capable of changing a zoom magnification of a projection image, executes focusing based on the distance measured by the distance measuring unit and projects an image on the screen; and an elevation angle control unit that controls an elevation angle of the distance measuring unit based on the zoom magnification set by the zoom mechanism unit in such a way that a distance measuring center line of the distance measuring unit corresponds to a center point of a projection area of the projection image, wherein the center point of a projection area is determined according to the zoom magnification of the zoom mechanism unit.

Abstract: Providing a zoom lens system having excellently correcting various aberrations with accomplishing to be compact, lightweight, and slim upon being retracted. The system is composed of, in order from an object, a first group having negative refractive power, and a second group having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first group and the second group varies. The first group is composed of two lens elements which are, in order from the object, a negative lens having a concave surface facing an image, and a positive lens. The second group consists of three lens elements or less and includes, in order from the object, a positive lens, an aperture stop for defining an f-number, and a negative lens component including a negative lens and disposed to the image side of the aperture stop. Given conditions are satisfied.

Abstract: An objective lens for endoscope comprises, in order from an object side, a front lens group having negative refractive power as a whole; a brightness aperture stop; and a rear lens group having positive refractive power as a whole, wherein said front lens group comprises in order from the object side, a first lens having negative refractive power; and a second lens group where a lens surface closest to the image side is convex form directed toward the image side, and it has positive refractive power as a whole; and the following condition (1) is satisfied: |f0/f1|?1.1 ??(4) where f0 is a composite focal length of said front lens group, and f1 is a focal length of said the first lens.

Abstract: A variable power optical system is provided and includes: in order from the object side, a first lens group having a negative refractive power and including a negative lens group and a positive lens group; a stop; and a second lens group having a positive refractive power and including a sub-lens group on the most object side, the sub-lens group including a first lens having a positive refractive power having at least one aspherical surface, a second lens having a positive refractive power, and a third lens having a positive refractive power. The second lens group is moved to the object side along an optical axis thereof to perform a variable power operation from a wide angle end to a telephoto end of the variable power optical system, and the first lens group is moved to make a correction of an image plane position in accordance with the variable power operation.

Abstract: A variable power optical system is provided and includes: in order from the object side, a first lens group having a negative refractive power and including a negative lens group and a positive lens group; a stop; and a second lens group having a positive refractive power and includes a sub-lens group having a positive refractive power as a whole and arranged on the most object side, the sub-lens group including a first lens having a positive refractive power having at least one aspherical surface, a second lens having a negative refractive power, and a third lens having a positive refractive power. The second lens group is moved to the object side along an optical axis to perform a variable power operation from the wide angle end to the telephoto end with moving the first lens group to make a correction of an image plane position.

Abstract: An exemplary projection lens includes, in this order from the screen-side thereof, a negative lens group having negative refraction of power, and a positive lens group having positive refraction of power. The positive and negative lens groups each include a number of positive and negative lenses. The focal length of the projection lens is adjustable. The projection lens satisfies the formulas of: ?2<F1/Fw<?1.6; 1.2<F2/Fw<1.4; and Vg2>56, where F1, and F2 respectively represent the effective focal lengths of the negative lens group and the positive lens group, Fw is the shortest effective focal length of the projection lens, and Vg2 is the average of the Abbe numbers of the positive lenses in the positive lens group.

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 two-unit zoom lens system includes in order from an object side thereof, a first lens unit G1 having a negative refracting power, a second lens unit G2 having a positive refracting power, and an aperture stop which is disposed between the first lens unit G1 and the second lens unit G2, and which moves integrally with the second lens unit. At a time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit G1 and the second lens unit G2 is narrowed. At the time of zooming from the wide angle end to the telephoto end, the first lens unit G1, after moving toward an image side, moves toward an object side. At the time of zooming from the wide angle end to the telephoto end, the second lens unit G2 moves toward the object side. The second lens unit G2 includes in order from the object side thereof, a front sub-unit having a positive refracting power, and a rear sub-unit having a negative refracting power.

Abstract: The invention relates to an reimaging optical system that has a sufficiently enhanced magnification and better performance, and an endoscope using the same. The reimaging optical system 3 is adapted to re-form an image by an image guide 6 on a solid-state imaging device 4 having a diagonal length of 6.5 mm or longer, and satisfies the following condition. 0.6<(D×?)/V ??(1) Here D is the diameter of the image guide 6, ? is the optical transverse magnification of the reimaging optical system 3, and V in mm is the minor axis direction length of an imaging area of the solid-state imaging device 4.

Abstract: In zooming, an optical unit moves the lens unit located at the most image side and the image sensor along the optical axis while not moving at least one lens unit, of a plurality of lens units, other than the lens unit located at the most image side.

Abstract: An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an object side of the aperture stop, the positive lens group has a cemented lens which is formed by cementing a plurality of lenses, in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditional expressions (2a) and (3a). 1.45<?<2.15??(1a) 1.30<Nd<2.

Abstract: A zoom lens includes a first lens unit having a negative refractive power and a second lens unit having a positive refractive power, which are arranged in order from the object side to the image side. The zoom lens performs zooming by changing a distance between the lens units. The first lens unit includes a compound optical element including a lens element and a resin layer having optical characteristics different from optical characteristics of the lens element, the resin layer being laminated on the lens element. An Abbe number ?dg of a material of the lens element, an Abbe number ?dj of a material of the resin layer, and an anomalous partial dispersion ratio ??gFj of the material of the resin layer are adequately set.

Abstract: An infrared lens system including a focus section that focus infrared radiation at an image plane, and a zoom section that adjusts a desired focal length of the infrared radiation, the focus section and zoom section including a plurality of lens elements which are located along an optical axis in optical communication with each other, the focus section and zoom section each including a fixed lens fixed with respect to the optical axis and a movable lens arranged for movement along the optical axis.

Abstract: An exemplary zoom lens system includes a negative first lens group and a positive second lens group. The first lens group includes a meniscus-shaped first lens with negative refracting power and a second lens with positive refracting power. The first lens has a concave surface facing an image side. The second lens group includes an aperture stop, a biconvex third lens with positive refracting power, and a meniscus-shaped fourth lens with negative refracting power. The fourth lens has a concave surface facing an object side. The first lens, the second lens, the aperture stop, the third lens and the fourth lens are aligned in that order from the object side to the image side.

Abstract: A zoom lens is disclosed. The zoom lens comprises a first lens group located adjacent to an object side and having a negative refractive power, and a second lens group located adjacent to an image side and having a positive refractive power, wherein zooming is made as an interval between the first lens group and the second lens group is varied.

Abstract: An intermediate telephoto lens system includes a positive front lens group, a variable-aperture diaphragm, and a positive rear lens group, in this order from the object. The positive front lens group includes a positive first lens element L1, a positive second lens element L2 and a negative third lens element L3, in this order from the object. The positive rear lens group includes cemented lens elements having a negative fourth lens element L4 and a positive fifth lens element L5, and a positive sixth lens element L6, in this order from the object. The intermediate telephoto lens system satisfies the following condition: 2.0<f/f12<3.0??(1) wherein f designates the focal length of the entire intermediate telephoto lens system; and f12 designates the combined focal length of the positive first lens element L1 and the positive second lens element L2.

Abstract: A power varying operation is performed by moving four lens groups out of six lens groups. A reduction side of a zoom lens is constructed as a substantially telecentric system. An aspheric lens is arranged in a pupil neighboring position where an effective aperture becomes smallest. Conditional Expressions (1) to (5) are satisfied. 1.2?bf/fw??(1) |fa/fw|?4.5??(2) ?a/?im?1.0??(3) |ffaw/fw|?1.5??(4) E?300×10?7(/° C.

Abstract: A zoom lens system excellently correcting various aberrations with accomplishing compactness, lightweight, and slimness upon accommodating lens barrel. The system consists of, in order from an object, a first group G1 having negative power, and a second group G2 having positive power. Upon zooming from a wide-angle end to a telephoto end, a distance between the first group G1 and the second group G2 decreases. The first group G1 consists of, in order from the object, a first lens L1 with negative power, and a second lens L2 with positive power. The second group G2 consists of three lenses that are, in order from the object, a third lens L3 with positive power, a fourth lens L4 with negative power having a convex surface facing the object, a fifth lens L5 with positive power. The three lenses are disposed without cemented each other. Given condition is satisfied.

Abstract: An imaging lens is used for forming an image of an object on an image-taking surface of a solid state image sensor element and includes, in order from an object side to an image surface side, a diaphragm, a first lens which is a meniscus lens having a positive power whose convex surface faces the object side, and a second lens which is a meniscus lens having a positive power whose convex surface faces the image surface side, wherein a condition expressed by the following expression is to be satisfied: 1.45?(r3+r4)/(r3?r4)?3.4, where, r3: center radius curvature of the object side face of the second lens, and r4: center radius curvature of the image surface side face of the second lens.

Abstract: Providing a high zoom ratio zoom lens system having a short total lens length and a small diameter of the first group despite of securing excellent optical performance, a half angle of view of 3.5° or less in the telephoto end, an f-number of 6 or less in the telephoto end, and a zoom ratio of about 10 or more. The system is composed of a first group having positive power, a second group having negative power, a third group having positive power , and a fourth group having positive power. The first group is composed of, in order from the object, a negative meniscus lens having a convex surface facing the object, a first positive lens having a convex surface facing the object, and a second positive lens. All groups moves along the optical axis upon zooming from a wide-angle end to a telephoto end. Given conditions are satisfied.

Abstract: An electronic imaging apparatus comprises a zoom lens including at least two lens groups and adapted to implement zooming by changing the spacing between the respective lens groups, and an electronic imaging device. The zoom lens includes at least one positive lens on an imaging device side with respect to an aperture stop, and satisfies the following conditions (1), (2) and (3). |?t??w|>8 ??(1) 1.0×10?3<P<4.

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: A zoom lens includes, in order from the object side thereof, a first lens unit G1 having a negative refracting power and a second lens unit G2 having a positive refracting power. During zooming from the wide angle end to the telephoto end, the distance between the first lens unit G1 and the second lens unit G2 decreases. Letting the term “lens component” refer to a lens member whose surfaces that are in contact with air on the optical axis include only two surfaces, one being an object side surface and the other being an image side surface, the first lens unit G1 is comprised of a negative lens component in the form of a cemented lens having a negative refracting power that has, in order from the object side, a negative lens having a concave surface directed toward the image side and a positive lens having a convex surface directed toward the object side, and the second lens unit G2 includes a lens component in the form of a cemented lens having at least one negative lens and a positive lens.

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 imaging optical system includes in order from an object side thereof a front lens unit having a negative refracting power, an aperture stop, and a rear lens unit having a positive refracting power, and the front lens unit having a negative refracting power includes in order from the object side, a first lens having a negative refracting power, and the rear lens unit having a positive refracting power includes in order from the object side, a second lens which is a positive lens, a third lens which is a negative lens, and a fourth lens which is a positive lens, and the imaging optical system satisfies the following conditional expressions (1) and (2) 1.6<|fG1|/FA<5??(1) 1.2<fG2/FA<5??(2) where, FA denotes a focal length of the overall imaging optical system, fG1 denotes a focal length of the front lens unit having a negative refracting power, and fG2 denotes a focal length of the rear lens unit having a positive refracting power.

Abstract: An imaging lens including, in order from an object side towards an image surface side, a diaphragm, a first lens which is a meniscus lens having a positive power whose convex surface faces the object side, and a second lens which is a lens having a positive power whose convex surface faces the image surface side, wherein conditions expressed by each of following expressions (1)-(6) are to be satisfied; 1.25?L/fl?0.8, 0.55?f1/f2>0, 1.5?f1/fl?0.9, 1?d2/d1?0.2, 0.35?d1/fl?0.1, and 0.27?d3/fl?0.1 (where, L: entire length of the imaging lens, fl: focal distance of the entire imaging lens, f1: focal distance of the first lens, f2: focal distance of the second lens, d1: center thickness of the first lens, d2: space between the first lens and the second lens on the optical axis, and d3: center thickness of the second lens).

Abstract: A digital camera and a mobile information terminal apparatus including a lens barrel including a first lens group and a second lens group disposed on an optical axis and configured to be related to operations concerned with changing overall relative magnification, a third lens group disposed on the optical axis and configured to be related to operations concerned with changing overall relative magnification and to be retracted from the optical axis in a collapsed state, a first driving device configured to drive the first lens group and the second lens group, a second driving device configured to drive the third lens group, a CCD disposed on the optical axis and configured to photograph a subject, a distance determining device configured to determine a distance to the subject, and a floating control device configured to drive at least one of the first driving device and the second driving device based on distance information obtained from the distance determining device to change an interval between the first