Abstract: An optical system including five lens units having, in order from the object side, positive, negative, positive, negative, positive refracting powers respectively. The distances between the lens units change during zooming. The first and third lens units are located closer to the object side at the telephoto end than at the wide angle end of the zoom range. The first lens unit includes a negative lens, a first positive lens, and a second positive lens. The second lens unit includes a plurality of negative lenses and at least one positive lens. The third lens unit includes a plurality of positive lenses and at least one negative lens. The fourth and fifth lens units each include two lenses or less. The refractive indices of the at least one negative lens in the first lens unit, the at least one positive lens in the second lens unit, and the at least one negative lens in the third lens unit are not lower than 1.9. The optical system satisfies a certain condition.

Abstract: A zoom lens including, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, an image side lens group having a positive refractive power, wherein the distance between the first lens group and the second lens group changes during zooming, a refractive optical element A, which has a positive refractive power when its object side surface and image side surface are exposed to air, is provided in the first lens group and located closest to the object side in the first lens group, and the refractive optical element A is cemented together with an optical element B. The Abbe constant ?d and the partial dispersion ratio ?gF of the refractive optical element A satisfies certain conditions.

Abstract: A zoom lens including, in order from the object side to the image side, a first lens group including a positive refractive power, a second lens group having a negative refractive power, an image side lens group having a positive refractive power, wherein the distance between the first lens group and the second lens group changes during zooming, and a refractive optical element A, which has a positive refractive power when its object side surface and image side surface are exposed to air, is provided in the first lens group and located closest to the object side in the first lens group, and the refractive optical element A is cemented together with an optical element B. The Abbe constant ?d and the relative partial dispersion ?gF of the refractive optical element A satisfies certain conditions.

Abstract: In an image forming optical system which includes in order from an object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a fourth lens group G4, and which includes maximum of five lens groups, and at the time of zooming from a wide angle end to a telephoto end, when a focal length of the overall image forming optical system is in a range of 1.2 fw to 1.8 fw, the first lens group G1 moves to be positioned more toward the object side than a position at the wide angle end, in a rectangular coordinate system in which, a horizontal axis is let to be ?d(LA) and a vertical axis is let to be nd(LA), when a straight line expressed by nd(LA)=a×?d(LA)+b(LA)(provided that a=?0.0267) is set, the image forming optical system satisfies a predetermined conditional expression.

Abstract: The present invention is directed to provide an enhanced variable power zoom lens that is lightweight as a whole, and especially, has its focusing lens optics reduced in weight so as to relieve of a load on a focusing drive system, and that has its anti-vibration lens optics reduced in both diameter and weight so as to relieve of a load on an anti-vibration drive system and downsize the same.

Abstract: An image forming optical system includes in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and an image-side lens group having a positive refractive power. A distance between the first lens group and the second lens group changes at the time of zooming. A refractive optical element A having a positive refractive power is positioned in the first lens group. The image forming optical system satisfies the following conditional expression (1-1), conditional expression (1-2), and conditional expression (2). ?dA<30??(1-1) 0.54<?gFA<0.9??(1-2) |fG1/fG2|>6.4??(2).

Abstract: Including, in order from an object side: a first lens group G1 having positive power; a second lens group G2 having negative power; a third lens group G3 having positive power; a fourth lens group G4 having negative power; and a fifth group G5 having positive power, an aperture stop being disposed to an image side of the second lens group, upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group G1 and the second lens group G2 increasing, a distance between the second lens group G2 and the third lens group G3 decreasing, a distance between the third lens group G3 and the fourth lens group G4 varying, and a distance between the fourth lens group G4 and the fifth lens group G5 varying, and given conditionals being satisfied, thereby providing a zoom lens system having high optical performance with suppressing variation in aberrations, an optical apparatus equipped therewith, and a method for manufacturing the zoom lens system.

Abstract: A zoom lens includes first, second, and third lens groups having positive, negative, and positive refractive powers, respectively, which are arranged in order from the object side to the image side. When zooming from wide-angle to telephoto, the first lens group moves to the object side, and spacings between the lens groups change. The third lens group has at least two lenses including a positive lens arranged closest to the object side. Blur correction on the image plane is performed by moving the positive lens of the third lens group perpendicularly to the optical axis. The zoom lens satisfies the following conditional expression (1): 0.3<(1??kFW)·?kRW<1.9??(1) where ?kFW and ?kRW are respectively the lateral magnifications at wide-angle of the positive lens arranged closest to the object side in the third lens group, and of a lens group including all lenses arranged closer to the image side than the positive lens.

Abstract: An image forming optical system has a positive lens group disposed closer to its object side than an aperture stop, and the values of ?gF1 and other constants of at least one lens LA included in the positive lens group fall within three ranges including a range bounded by the straight lines given by the equation ?gF1=?1×?d1+?gF1 (where ?1=?0.00566) into which the lowest and highest values in the range given by a first conditional expression are substituted respectively, a range bounded by the straight lines given by the equation nd1=a1×?d1+b1 (where a1=?0.0267) into which the lowest and highest values in the range given by a second conditional expression are substituted respectively, and a range defined by a third conditional expression.

Abstract: A zoom lens system comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, a fourth lens unit having negative optical power, and a fifth lens unit having positive optical power, wherein the third lens unit includes at least one lens element having positive optical power and at least one lens element having negative optical power, at least the first to third lens units are moved along an optical axis in zooming so that air spaces between the respective lens units vary, thereby performing magnification change, a lens unit positioned on the image side relative to an aperture diaphragm is moved along the optical axis in focusing, and the conditions: 4.0<D/Ir<5.3 and Z=fT/fW?9.

Abstract: A zoom lens system comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, a fourth lens unit having negative optical power, and a fifth lens unit having positive optical power, wherein the third lens unit includes at least one lens element having positive optical power and at least one lens element having negative optical power, at least the first to third lens units are moved along an optical axis in zooming so that air spaces between the respective lens units vary, thereby performing magnification change, a lens unit positioned on the image side relative to an aperture diaphragm is moved along the optical axis in focusing, and the conditions: 8.1<fG1/Ir<10.4 and Z=fT/fW?9.

Abstract: A zoom lens ZL including an optical element P for deflecting an optical path, including, in order from an object: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; a third lens group G3 having positive refractive power; a fourth lens group G4 having positive refractive power; a fifth lens group G5 having negative refractive power; and a sixth lens group G6, wherein a conditional expression 0.10<fw/PL<0.45 is satisfied, where fw denotes a focal length of the zoom lens ZL in a wide-angle end state, and PL denotes an optical path length of the optical element P for deflecting the optical path.

Abstract: A compact wide-angle zoom lens and an image pickup device having the same. The zoom lens includes a first lens group having a negative refractive power and a second lens group having a positive refractive power in an order from an object side to an image side, performs zooming by varying a distance between the first and second lens groups, and performs focusing by using a first lens closest to the object side in the second lens group.

Abstract: A compact zoom lens with three lens groups and a design method thereof. Along the optical axis from the object side to the image side, the compact zoom lens with three lens groups includes a negative power first lens group having a negative power first lens and a positive power second lens, a positive power second lens group having a positive power third lens, a negative power fourth lens leaned with the third lens and a positive power fifth lens, and a third lens group having a positive power sixth lens. The zoom lens matches requirements of optical properties for aberration correction. Minimum change of the distance between the first lens of the first lens group and the image forming plane from the WIDE position to the TELE position is used as the objective function of optimization.

Abstract: A zoom lens includes 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 positive refractive power in order from the object side to the image side. The first lens unit includes a negative lens and a positive lens. When the curvature radius of the object side surface and that of the image side surface of the negative lens are respectively defined as R11 and R12 and the curvature radius of the object side surface and that of the image side surface of the positive lens are respectively defined as R21 and R22, the following conditional expression is satisfied: ?5.6<(R12+R21)/(R12?R21)<?4.7 and 1.5<(R11+R22)/(R11?R22)<2.3.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a rear lens unit including one or more lens units. An interval between respective adjacent lens units varies during zooming such that an interval between the first lens unit and the second lens unit is larger at a telephoto end than at a wide-angle end and an interval between the second lens unit and the third lens unit is smaller at the telephoto end than at the wide-angle end. The third lens unit includes at least one negative lens. An Abbe number (?d3n) and a relative partial dispersion (?gF3n) of a material of the negative lens are appropriately set based on predetermined conditional expressions.

Abstract: In a zoom lens ZL1 having a plurality of lens groups G1 to G2 which are disposed in order from an object, where a refractive index average value of the lens components which constitute the zoom lens ZL1 is defined as ndav and a refractive index average value of the lens components which constitute the first lens group G1 which is disposed to closest to the object among the plurality of lens groups G1 to G2 is defined as ndGlav, the zoom lens ZL1 is constituted to satisfy the conditional expression ndav?1.80 and to satisfy the conditional expression ndGlav?1.85.

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 zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming, wherein a lens unit located closest to an object side is fixed relative to an image surface at the time of zooming, at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing in at least one zooming position, and the condition: 0.1<T1/fW<1.5 (T1: an axial thickness of the lens unit located closest to the object side, fW: a focal length of the entire system at a wide-angle limit) is satisfied; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A zoom lens system, in order from the object side to the image side, comprising a first lens unit, a second lens unit, a third lens unit and subsequent lens units including at least a fourth lens unit, wherein an aperture diaphragm is either included in the third lens unit or located on the image side relative to the third lens unit, at least two among the first to third lens units and the subsequent lens units are movable lens units which individually move along an optical axis at the time of zooming, 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 at least the second lens unit and one of the subsequent lens units are the focusing lens units; an interchangeable lens apparatus; and a camera system are provided.

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: The zoom lens is a retractable bent-type zoom lens capable of providing a high zoom ratio and a reduced thickness, and capable of retracting into a camera body with an easily-configured mechanism. The zoom lens includes in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a prism including a reflective surface, and a posterior lens group which includes plural lens units and has as a whole a positive refractive power. The first and second lens units are retractable into a space formed by movement of the prism in a direction orthogonal to an optical axis of the first lens unit, and, during zooming, the second lens unit and the plural lens units in the posterior lens group are moved while the first lens unit and the prism are fixed.

Abstract: A zoom lens includes a first lens group including an optical path change member that changes an optical path, a second lens group including at least one negative lens and at least one positive lens, and lens groups having a positive refractive power. The first lens group is closer to an object side of the zoom lens and is fixed relative to an image plane during a zooming operation. The second lens group is adapted to move during the zooming operation. Each of the lens groups includes at least one positive lens, and the lens groups are closer to an image plane side of the zoom lens. The zoom lens satisfies vdLP>71, vdL2p<40, and ndL2m>1.71, wherein “vdLP” is an Abbe number, “vdL2p” is an Abbe number, and “ndL2m” is a refractive index.

Abstract: A zoom lens includes, in order from an object side to an image plane side, a first lens group fixed to the image plane during zooming, having a positive refractive power, and including a single lens having a negative refractive power, an optical path change member for changing an optical path, and a positive lens group having a positive refractive power, which are arranged in order from the object side, a second lens group having a negative refractive power and including a negative lens group and a positive lens group which are arranged in order from the object side with an air gap, a third lens group fixed to the image plane during zooming and having a positive refractive power, and at least one lens group having a positive refractive power. The zoom lens satisfies the conditions the 1.4<|fLG1/fw|<5.8 and ?4.8<Ept/Yimg<?2.5.

Abstract: An image forming optical system comprising, in order from the object side: a first lens group G1 that is fixed during zooming and includes a reflecting optical element for bending an optical path; a second lens group G2 having a negative refracting power and movable during zooming; a third lens group G3 having a positive refracting power; a fourth lens group G4 having a positive refracting power; and a rearmost lens group GR, wherein during zooming from the wide angle end to the telephoto end, the third lens group G3 moves on the optical axis toward the object side, characterized in that the rearmost lens group GR satisfies the following condition: 0.95<?Rw<2.5 . . . (1-1).

Abstract: A zoom lens system, in order from an object side to an image side, comprising a first lens unit of positive power, a second lens unit of negative power, a third lens unit of positive power, and a fourth lens unit of positive power, wherein in zooming, the first to the fourth lens units are moved along the optical axis such that the air spaces between the individual lens units should vary, so that magnification change is achieved, and wherein the conditions: ?0.60<M2/fG2<?0.07, ?W?30, and fT/fW?4.5 (M2 is an amount of axial movement of the second lens unit in zooming, fG2 is a composite focal length of the second lens unit, ?W is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system at a telephoto limit and at a wide-angle limit, respectively) are satisfied, an imaging device and a camera are provided.

Abstract: A zoom lens system includes, in order from an object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a position of the first lens group is fixed. At least a portion of any one of the lens groups is moved in a direction including a component perpendicular to an optical axis, and a given conditional expression is satisfied, thereby providing a zoom lens system capable of excellently suppressing variation in aberrations upon zooming and upon correcting an image blur, an optical apparatus including the zoom lens system, and a method for manufacturing the zoom lens system.

Abstract: The optical system includes first (positive) and second (negative) lens units arranged in order from an object side to an image side, and an aperture stop disposed further on the image side than the second lens unit. The first lens unit includes at least one first optical element satisfying ?GH>0.0, ?dGH<39.5 and ndGH>1.70. The optical system satisfies 0.65<|?2/?1|<6.00 and 0.45<|??GH×?2/?12|<4.00. ?GH represents a refractive power of the first optical element when light-entrance and light-exit surfaces thereof are in contact with air, ?dGH and ndGH respectively represent an Abbe number and a refractive index of a material forming the first optical element for a d-line, ?1 and ?2 respectively represent the refractive powers of the first lens unit and the second lens unit, and ??GH represents a sum total of the refractive power ??GH of the at least one first optical element.

Abstract: A zoom lens includes: a first lens group including a reflection member that deflects an optical path by 90 degrees and having positive refracting power; a second lens group having negative refracting power; a third lens group having positive refracting power; at least one lens group having negative refracting power and at least one lens group having positive refracting power disposed as a fourth lens group and the following lens groups, the first to third lens groups and the fourth and following lens groups arranged in this order from an object side toward an image side; and an aperture diaphragm disposed in the vicinity of the third lens group, wherein in zooming from a wide angle end state to a telescopic end state, the first lens group is fixed, the second lens group is moved toward the image side, and the fourth lens group is moved toward the object side, and the zoom lens satisfies the following conditional equation 1<(R1B+R21A)/(R1B?R21A)<20.

Abstract: An imaging apparatus includes a first lens has a positive refractive power, a second lens has a positive refractive power, a third lens has a negative refractive power, a fourth lens has a negative refractive power, an image sensor and a driving device. The first lens, the second lens, the third lens, the fourth lens and the image sensor are arranged in the order written along an optical axis of the imaging apparatus from the object side to the image side thereof. The driving device is connected to the second lens and configured for driving the second lens to move toward the object side to perform a zoom-in function of the imaging apparatus.

Abstract: A zoom lens includes: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; a fourth lens group having a positive refracting power; and a fifth lens group having a positive or negative refracting power; the first, second, third, fourth and fifth lenses being disposed in order from the object side to the image side of the zoom lens.

Abstract: A lens control device which is capable of controlling lens positions such that an in-focus state of an object image can be maintained even when a variable power lens is positioned outside a normal zoom range from a wide-angle end to a telephoto end. A flash memory stores a positional relationship between the variable power lens and a focus lens, on an object distance-by-object distance basis. A system controller controls the movement of the focus lens by calculating the in-focus position of the focus lens with respect to the position of the variable power lens based on the positional relationship stored in the flash memory when the variable power lens is moved to a position outside the normal zoom range defined in the positional relationship stored in the flash memory.

Abstract: An object is to reduce the effect of defocusing due to the movement of an image plane when a shifting lens group movable in a direction perpendicular to the optical axis for correcting hand jiggling is positionally deviated along the optical axis, thereby maintaining high optical performance at the time of correcting hand jiggling. A zoom lens 1 includes a plurality of lens groups with distances between the lens groups being changed for variable power. A final lens group L5 which is positioned most closely to an image side has a sub lens group GS (G8) having a positive refractive power and a sub lens group GR (G9) disposed adjacent to the sub lens group GS (G8) on the image side and having a positive refractive power. The sub lens group GS is shiftable in a direction perpendicular to the optical axis for correcting image blurs.

Abstract: There is provided an image forming optical system in which, it is possible to achieve both, the small-sizing and slimming of an optical system, and a favorable correction of various aberrations, mainly the chromatic aberration. In an image forming optical system including a lens component in which, a shape of another optical surface C of an intermediate layer L2 which is made of a transparent material having Abbe's number ?d2 which is in a close contact with one optical surface B of a lens L1 which is made of a transparent material having Abbe's number ?d1, is an aspheric shape differing from (a shape of) the optical surface B, and furthermore, a lens L3 which is made of a transparent material having Abbe's number ?d3 is in a close contact with the optical surface C, the following conditions are satisfied 0.012<1/?d3?1/?d1<0.090??(1) 0.

Abstract: This is addressed to provide a zoom lens which has a good optical performance for imaging device having a large number of pixels even with its simple construction, and which can also be small and thin in structure, and an imaging apparatus using the zoom lens. A zoom lens 1 is composed by arranging, in the following order from an object side, a first lens group GR1 having a weak refractive power, a second lens group GR2 having a negative refractive power, a third lens group GR3 having a positive refractive power, and a fourth lens group GR4 having a positive refractive power, and is configured to perform zooming by moving the second lens group and the third lens group. The first lens group is composed by arranging, in the order from an object side, a single lens G1 having a a negative refractive power, a prism G1 for folding an optical path, and a single lens G3 having a a positive refractive power.

Abstract: The present invention relates to a zoom lens which can shift images using a movable optical system so as to have components orthogonal to the optical axis, and can correct hand motion blur, and minimizes the deterioration of performance while attempting higher variable power. This zoom lens has, in order from an object, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power, and at least a part of the fourth lens group G4 can move so as to have components orthogonal to the optical axis, and a distance between each lens group is changed upon zooming from a wide-angle end state to a telephoto end state, and the following conditional expression is satisfied, 0.01<f5/ft<0.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a subsequent lens unit including at least two lens units. An interval between respective adjacent lens units varies for zooming. The first lens unit includes a positive lens and a negative lens.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a rear group including at least one lens unit. For zooming from a wide angle end to a telephoto end, the first lens unit moves to the object side, the second lens unit moves to the image side, and the third lens unit moves to the object side. Moving amounts of the first lens unit, the second lens unit, and the third lens unit for zooming from the wide angle end to the telephoto end and focal lengths of the second lens unit and the third lens unit are set based on predetermined conditions.

Abstract: In a zoom lens ZL having a plurality of lens groups which are disposed in order from an object, a first lens group that is disposed to closest to the object among the plurality of lens groups has positive refractive power and comprises a light path bending element which bends the path of light and a plurality of lens components which are disposed closer to the object than the light path bending element, and the plurality of lens components comprise at least one negative lens whose refractive index with respect to d-line exceeds 1.90.

Abstract: The invention relates to an eyepiece optical system that, albeit being of small size, works in favor of gaining an angle of field and optical performance, and an electronic view finder incorporating such an eyepiece optical system. Specifically, the invention is characterized by comprising, in order from an object side to an exit side thereof, a first lens group that is a single lens that has positive refracting power and is in a meniscus configuration concave on its object side, a second lens group that is a single lens that has negative refracting power and is in a meniscus configuration concave on its object side, and a third lens group that is a single lens that has positive refracting power, wherein an object-side concave lens surface in the first lens group is an aspheric surface, an object-side concave lens surface in the second lens group is an aspheric surface, and an exit-side lens surface in the third lens group is an aspheric surface.

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: Disclosed herein is a zoom lens including a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group. The zoom lens satisfies following conditional expressions (1) and (2), 0.03<H1?/f1<0.3??(1) 0.3<|f2|/?(fw·ft)<0.65??(2) where H1? is an interval from a vertex of a surface nearest to the image side in the first lens group to a principal point on the image side of the first lens group (? denotes the object side, and + denotes the image side), f1 is focal length of the first lens group, f2 is focal length of the second lens group, fw is focal length of an entire lens system at a wide-angle end, and ft is the focal length of the entire lens system at a telephoto end.

Abstract: A small zoom lens having a high zoom ratio and high optical performance over an entire zoom range is obtained. The zoom lens includes, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; a fourth lens unit having a negative refractive power; and a fifth lens unit having a positive refractive power, wherein intervals between the first lens unit, the second lens unit, the third lens unit, the fourth lens unit, and the fifth lens unit are changed during zooming, in which a focal length (fw) of an entire system at a wide angle end and a focal length (fn) of an n-th lens unit are set appropriately.

Abstract: Provided is a zoom lens including, in order from an object side to an image side: a positive first lens unit having two positive lenses and a negative lens; a negative second lens unit having positive and negative lenses; a positive third lens unit; and a rear group including lens unit, wherein: with respect to a wide angle end, at a telephoto end, intervals between the first and second lens units, the second and third lens units, and the third lens unit and the rear group respectively change; and a focal length and an Abbe number of a material of the positive lens of the first lens unit that has a largest Abbe number among positive lenses, a refractive index and an Abbe number of a material of the positive lens of the second lens unit, and a focal length of the first lens unit are set appropriately.

Abstract: The invention relates to an eyepiece optical system that, albeit being of small size, works in favor of gaining an angle of field and optical performance, and an electronic view finder incorporating such an eyepiece optical system. Specifically, the invention is characterized by comprising, in order from an object side to an exit side thereof, a first lens group that is a single lens that has positive refracting power and is in a meniscus configuration concave on its object side, a second lens group that is a single lens that has negative refracting power and is in a meniscus configuration concave on its object side, and a third lens group that is a single lens that has positive refracting power, wherein an object-side concave lens surface in the first lens group is an aspheric surface, an object-side concave lens surface in the second lens group is an aspheric surface, and an exit-side lens surface in the third lens group is an aspheric surface.

Abstract: A zoom lens and a photographing apparatus including the same. The zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and an additional lens grouping having a positive refractive power, which are sequentially arranged from an object side, wherein the additional lens grouping comprises a third lens group having a positive refractive power.

Abstract: A zoom lens includes: a first lens group having a positive refracting power; a second lens group having a negative refracting power; a third lens group having a positive refracting power; a fourth lens group having a positive refracting power; and a fifth lens group having a positive or negative refracting power; the first, second, third, fourth and fifth lenses being disposed in order from the object side to the image side of the zoom lens.

Abstract: A zoom lens ZL, which is mounted on an electronic still camera 1 or the like, is composed of, in order from the object side, a first lens unit G1 having a positive refractive power, a second lens unit G2 having a negative refractive power, a third lens unit G3 having a positive refractive power, a fourth lens unit G4 having a negative refractive power, and a fifth lens unit G5 having a positive refractive power. The first lens unit G1 has, in order from the object side, a negative meniscus lens with a convex surface on the object side, and a positive lens, and the second lens unit G2 has, in order from the object side, a negative meniscus lens with a convex surface on the object side, a biconcave lens, and a positive lens. The zoom lens satisfies a condition of the following expression: 0.005<(?f2)×f3/(f12)<0.023, where f1, f2, and f3 are the respective focal lengths of the first, second, and third lens units G1, G2, and G3.

Abstract: A zoom lens includes, in order from an object-side to an image-plane-side: a positive first lens unit; a negative second lens unit; a stop; a positive third lens unit; a negative fourth lens unit; and a positive fifth lens unit, wherein: during zooming, the first lens unit moves along a locus convex toward the image-plane-side, the second lens unit moves toward the image-plane-side, and the stop moves; at the telephoto end compared with the wide angle end, an interval between the first lens unit and the second lens unit increases, an interval between the second lens unit and the third lens unit decreases, and an interval between the aperture stop and the third lens unit decreases, focal lengths of the fourth lens unit, a focal length of an entire system at the telephoto end, and a movement amount of the first lens unit are appropriately set.

Abstract: A lens optical system includes a first optical system which includes, in order from an object side to an image side along an optical axis, a first lens group having a positive refractive power and including a first reflection member to redirect an optical path of light representing an object from a first direction toward an image sensor, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power. During zooming from a wide mode to a tele mode, the first lens group and the fifth lens group are fixed, the second lens group moves toward the image side, the third lens group and the fourth lens group move toward the object side, and the fourth lens group performs focusing.