Abstract: A zoom lens comprises in order from an object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power, and the third unit having a positive refractive power comprises in order from the object side, a first lens component having a positive refractive power, and a second lens component having a negative refractive power in which, a lens having a positive refractive power and a lens having a negative refractive power are cemented, and the zoom lens satisfies the following conditional expressions (1), (2), and (3). 1.4<|f3_2p/f3_2n|<2.6??(1) nd3_2p?nd3_2n?0??(2) nd3_2n?1.8??(3).

Abstract: The zoom lens system includes a first lens group with positive power, a second lens group with negative power, a third lens group with positive power, a fourth lens group with negative power, and a fifth lens group with positive power. An aperture stop is provided between the second and the third lens groups. The third lens group includes lens element L3a and L3b with positive power, lens element L3c with negative power, and lens element L3d with positive power. The lens elements L3c and L3d are cemented. The lens element L3b corrects image blurring. The fourth lens group moves when focusing. When zooming, the first to the fourth lens group move. Here, condition (1) below is satisfied. 0.24<fL3b/fG3<3.0??(1) Where fL3b is a focal length of the lens element L3b, and fG3 is a focal length of the third lens group.

Abstract: A zoom lens includes a front unit having a negative refractive power and a rear unit having a positive refractive power, which includes an aperture stop, and the front unit includes a first lens having a negative refractive power, and the first lens has a meniscus shape of which a convex surface is directed toward the object side, and the rear unit includes a first lens unit A and a second lens unit B, and at the time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit changes.

Abstract: A zoom lens includes, in order from object side: a positive first unit not moving for zooming; a second unit moving during zooming; a positive third unit; a positive fourth unit; and a rear unit including at least one unit, the second unit including one or more lens sub-units and having a negative refractive power as a whole, the fourth unit moving during zooming, the zoom lens including a stop between the second and third units or between the third and fourth units. Lateral magnifications of the second unit at a wide angle end and a telephoto end when beam enters from infinity, focal lengths at the wide angle end and the telephoto end, a focal length of the first unit, and a focal length of the second unit at the wide angle end are appropriately set.

Abstract: A zoom lens system includes a first lens unit, a second lens unit, a third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit. In zooming, at least the first lens unit, the second lens unit, and the third lens unit move along an optical axis so that an interval between the first lens unit and the second lens unit at a telephoto limit becomes larger than that at a wide-angle limit, and an interval between the second lens unit and the third lens unit at the telephoto limit becomes narrower than that at the wide-angle limit. An aperture diaphragm is disposed between the second lens unit and the third lens unit. A condition of 18.5<fG1/fW<30.0 (fG1: a focal length of the first lens unit, fW: a focal length of the entire system at the wide-angle limit) is satisfied.

Abstract: A zoom lens is constituted by, in order from the object side to the image side: a positive first lens group; a positive second lens group; a negative third lens group; a negative fourth lens group; and a positive fifth lens group. The first lens group and the fifth lens group are fixed with respect to an image formation plane while the second lens group, the third lens group, and the fourth lens group move to change the distances among adjacent lens group when changing magnification. Conditional Formula (1) below is satisfied. 2.

Abstract: Composing, 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 positive refractive power and a fifth lens group; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied, and predetermined conditional expression being satisfied, thereby providing a small-size variable magnification optical system having a high zoom ratio and a high optical performance, an optical apparatus, and a method for manufacturing the variable magnification optical system.

Abstract: A photographing apparatus of the present invention, having a lens barrel including a photographing optical system for guiding photographing light flux and a camera body capable of being attached to and detached from the lens barrel, comprises an image sensor having pairs of focus detection pixels, a first memory for storing information relating to incident angle range of imaging light flux, a second memory, arranged in the body barrel, for storing information on light receiving sensitivity characteristic of the focus detection pixels, and a calculation controller for calculating information for focus adjustment control based on information that has been read out from the first memory and the second memory, wherein the information relating to incident angle range includes angular information of upper and lower ends of imaging light flux corresponding to image height.

Abstract: A zoom lens has a four-group zoom configuration, in order from the object side to the image side, consisting of negative, positive, positive, and positive refractive power. The zoom lens carries out zooming from the wide-angle end to the telephoto end mainly by changing the distance between the third lens group and the fourth lens group. Also, the distance between the second lens group and the third lens group may be decreased in the zooming. Focusing is carried out mainly by moving the second lens group along the optical axis. Such a zoom lens is thin and small in size, and has a great imaging performance.

Abstract: A zoom lens is provided. The zoom lens includes a first lens group, a second lens group, a third lens group and an aperture stop. The second lens group is disposed between the first lens group and the third lens group. The aperture stop is disposed between the first lens group and the second lens group. When the zoom lens zooms, the aperture stop is fixed without moving and the first lens group correspondingly moves.

Abstract: Provided is an optical system, which retains enhanced optical performance at any object distance, and has compact and light-weight focus lens units. Provided is an optical system including a plurality of lens units, in which an interval between adjacent lens units changes during focusing, the optical system including: a positive lens unit arranged closest to an object side; first and second focus lens units having negative refractive powers configured to move during focusing; and an intermediate lens unit having a positive refractive power and arranged between the first and second focus lens units. The first and second focus lens units are configured to move toward an image side during focusing.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first, third and fifth lens groups move in the optical axis direction. The second lens group includes at least four lens elements. Each of the third, fourth and fifth lens groups includes a plurality of lens elements. The following conditions (1) and (2) are satisfied: 1.60<f1/f5<2.46 ??(1), and ?2.46<f4/f3<?1.80 ??(2), wherein f1, f3, f4 and f5 designate the focal lengths of the first, third, fourth and fifth lens groups, respectively.

Abstract: A variable magnification optical system includes, in order from the object side: a positive first lens group; a negative second lens group; a positive third lens group; a negative fourth lens group; and a positive fifth lens group. When changing magnification from the wide angle end to the telephoto end, the first and third lens groups are fixed with respect to an image formation plane, the second lens group moves toward the image side, the fourth lens group moves, and the distance between the fourth and fifth lens groups changes. A rearward lens group constituted by the third, fourth, and fifth lens groups has a positive refractive power throughout the variable magnification range. The transverse magnification ratio of the fourth lens group when focused on an object at infinity is negative throughout the variable magnification range.

Abstract: An imaging lens is constituted by, in order from the object side to the image side: a positive first lens group; a stop; a negative second lens group; and a positive third lens group. Only the second lens group moves in the direction of the optical axis to perform focusing operations. The first lens group is constituted by, in order from the object side to the image side, a first lens group front group and a first lens group rear group. The first lens group front group is constituted by, in order from the object side to the image side, one positive lens and one negative lens, the first lens group rear group includes at least two negative lenses and at least three positive lenses. The second lens group is constituted by one or two positive lenses and one negative lens.

Abstract: A zoom lens consists of, in order from the object side, a positive first lens group that is fixed during magnification change, at least three movable lens groups that are moved during magnification change, and a positive end lens group that is disposed at the most image side and is fixed during magnification change. The at least three movable lens groups include, in order from the object side, a positive lens group, a negative lens group, and a negative lens group. The first lens group includes at least two negative lenses, where the most object-side negative lens has a meniscus shape with the convex surface toward the object side, and a first-n lens, which is at least one negative lens of the rest of the negative lenses of the first lens group, satisfies given condition expressions (1) and (2).

Abstract: A zoom lens consists of, in order from the object side, a positive first lens group that is fixed during magnification change, at least two movable lens groups that are moved during magnification change, and a positive end lens group that is disposed at the most image side and is fixed during magnification change. The first lens group consists of, in order from the object side, a negative first-a lens group that is fixed during focusing, a positive first-b lens group that is moved during focusing, and a positive first-c lens group. The first-a lens group includes at least two negative lenses, where the most object-side negative lens has a meniscus shape with the convex surface toward the object side, and a first-n lens, which is at least one negative lens of the rest of the negative lenses of the first-a lens group, satisfies given condition expressions (1) to (3).

Abstract: The zoom lens has an aperture stop arranged between the second lens unit and the fourth lens unit. During zooming from the wide angle end to the telephoto end, the distances between the lens units vary in such a way that the distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, the distance between the second lens unit and the third lens unit is smaller at the telephoto end than at the wide angle end, and the distance between the fourth lens unit and the fifth lens unit is larger at the telephoto end than at the wide angle end. The zoom lens satisfies the following conditional expression (1): 3.5?LTLw/IHt?8.9??(1).

Abstract: A zoom lens, including, in order from object side: a positive first unit which is fixed during zooming; a negative second unit which moves for zooming; a positive third unit which moves for zooming; a positive fourth unit which moves for zooming; and a positive fifth unit which is fixed during zooming, in which 1.50<LN(Z2)/LN(Z34)<2.30 and 0.70<f34w/f34t<0.96 are satisfied, where LN(Z2) is natural logarithm of Z2 obtained by dividing a lateral magnification ?2t of the second unit at telephoto end by a lateral magnification ?2w at wide angle end, LN(Z34) is natural logarithm of Z34 obtained by dividing a combined lateral magnification ?34t of the third unit and the fourth unit at telephoto end by a combined lateral magnification ?34w at wide angle end, and f34w and f34t are combined focal lengths of the third unit and the fourth unit at wide angle end and telephoto end, respectively.

Abstract: A zoom lens include, from an object side, a first magnification-varying group, an aperture stop and a second magnification-varying group, the first magnification-varying group including: a positive first lens unit configured not to move for zooming; a negative second lens unit configured to move during zooming; and one or more magnification-varying lens units configured to move during zooming, the magnification-varying lens units having a positive combined refractive power, the second magnification-varying group including: a negative first sub lens unit configured not to move for zooming; a negative second sub lens unit configured to move during zooming; and a positive third sub lens unit, the second magnification-varying group moving the second sub lens unit to the image side to displace a focal length range of the entire system toward a long focal length side.

Abstract: Certain exemplary embodiments can provide a system, machine, device, manufacture, circuit, composition of matter, and/or user interface adapted for and/or resulting from, and/or a method and/or machine-readable medium comprising machine-implementable instructions for, activities that can comprise and/or relate to, via a device comprising an electro-active lens, automatically acquiring at least two images of a scene.

Abstract: Methods and systems for providing a single stream including multiple FoVs. One system includes an image sensor configured to receive a selection of a plurality of field-of-views from a user, capture an image associated with each of the plurality of field-of-views, stitch the image associated with each of the plurality of field-of-views into a single stream, and transmit the single stream to at least one computing device.

Abstract: A five-group zoom lens including, in order from the object side, positive, negative, negative, positive, and positive groups. The first group includes a negative meniscus lens with the concave surface toward the image side, a positive lens and a positive lens. The second group includes a negative lens with the image-side surface having an absolute value of curvature radius smaller than that of the object side surface, a biconcave lens, and a biconvex lens. The third group includes a negative lens with the object side surface having an absolute value of curvature radius smaller than that of the image-side surface, and is moved during focusing on a closer object. The fifth group includes a positive fifth-A group including a biconvex lens, and a negative fifth-B group including a biconcave lens and a biconvex lens, wherein condition expression (1) is satisfied: ?4<f5/f5B<?0.7??(1).

Abstract: A zoom lens has a first positive lens unit having a positive refractive power, a second positive lens unit arranged adjacent to the first positive lens unit on its image side, a third positive lens unit arranged adjacent to the second positive lens unit on its image side, and a front lens group arranged on the object side of the first positive lens unit. Appropriate conditions concerning the refractive power of the front lens group, the focal length of the second positive lens unit, and the focal length of the zoom lens at the wide angle end are given.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, a third lens group including at least one positive lens element or one negative lens element, a positive fourth lens group, and a negative fifth lens group, in that order from the object side. At least the first, second, fourth and fifth lens groups are moved during zooming from the short to long focal length extremities, and the following conditions (1) and (2) are satisfied: ?6.5<f1/f5<?4.6??(1), and ?1.2<fw/f3<0.7??(2), wherein f1, f3 and f5 designate the focal lengths of the first and fifth lens groups, respectively, and fw designates the focal length of the entire zoom lens system at the short focal length extremity.

Abstract: A macro lens system includes, in this order from an object side: a positive first lens group; a negative second lens group; a positive third lens group; a positive fourth lens group; a positive fifth lens group; and a negative sixth lens group. The first lens group is constituted by three lenses. The second lens group, the fourth lens group, and the fifth lens group are independently moved in the direction of the optical axes thereof when focusing from an object at infinity to an object at a most proximate distance.

Abstract: A zoom lens includes: a first lens group having a positive refractive power which is fixed while changing magnification; two or more movable lens groups that move independently from each other while changing magnification; and a final lens group having a positive refractive power which is fixed while changing magnification, provided in this order from an object side. The zoom lens satisfying Conditional Formula (1) below: 1.30<h/(Yimg·tan ?)<2.37??(1).

Abstract: A dual-aperture zoom camera comprising a Wide camera with a respective Wide lens and a Tele camera with a respective Tele lens, the Wide and Tele cameras mounted directly on a single printed circuit board, wherein the Wide and Tele lenses have respective effective focal lengths EFLW and EFLT and respective total track lengths TTLW and TTLT and wherein TTLW/EFLW>1.1 and TTLT/EFLT<1.0. Optionally, the dual-aperture zoom camera may further comprise an optical OIS controller configured to provide a compensation lens movement according to a user-defined zoom factor (ZF) and a camera tilt (CT) through LMV=CT*EFLZF, where EFLZF is a zoom-factor dependent effective focal length.

Abstract: An image reading lens includes a plurality of lenses, a first correcting mechanism that corrects a field curvature at a first correction part when temperature changes, and a second correcting mechanism that corrects an image-forming position when the temperature changes. The second correcting mechanism corrects the image-forming position at a part where a positional displacement of the image-forming position caused by a change of a lens interval is greater and a variation of the field curvature caused by the change of the lens interval is smaller than the first correction part.

Abstract: Provided is a projection lens including: a first lens, a reflective optical device, a second lens and a third lens from an image side of the projection lens to an object side of the projection lens in turn. The first lens is of a negative focal power, an image side of the first lens is concave; the reflective optical device enables light to be bended; the second lens is of a positive focal power, an object side of the second lens is convex; the third lens is of a positive focal power, an object side of the third lens is convex. A diaphragm is arranged between first lens and second lens, the projection lens meets: 0.4<ImgH/D<0.7, wherein ImgH equals to a half-length of an object diagonal, D represents a vertical height from the image side of the first lens to a center axis perpendicular to an object.

Abstract: A zoom lens for projection consists of a negative first lens group, which is fixed during magnification change, a middle group, which includes plural lens groups that move during magnification change, and a positive last lens group, which is fixed during magnification change, in this order from a magnification side. A reduction side is non-telecentric. Both of a lens group closest to the magnification side and a lens group closest to the reduction side in the middle group have positive refractive power, and move from the reduction side toward the magnification side during magnification change from a wide-angle end to a telephoto end. The last lens group includes at least two positive lenses and at least two negative lenses. A positive lens is arranged closest to the reduction side in the last lens group. A predetermined conditional expression about a focal length of the last lens group is satisfied.

Abstract: A wide-angle lens system includes, in an order from an object side toward an image surface side: a first lens group having positive or negative refractive power; a second lens group having positive refractive power; and a third lens group having negative refractive power. When an object position changes from an infinite distance to a nearest distance, the first and third lens groups are fixed, and the second lens group moves along an optical axis to perform focusing.

Abstract: A zoom lens includes: 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 positive refractive power; a fifth lens group having negative refractive power; and a sixth lens group having positive refractive power. The first to sixth lens groups are arranged in order from an object side. A total length of the zoom lens varies when a lens position state varies from a wide end state to a telephoto end state. A focusing operation is performed through allowing the fifth lens group to travel along an optical axis in accordance with variation in a subject distance from infinite to a closer distance.

Abstract: A zoom lens system, in order from an object side to an image side, 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; a fifth lens unit; and a sixth lens unit, wherein in zooming from a wide-angle limit to a telephoto limit at a time of image taking, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit move along an optical axis so that an interval between the third lens unit and the fourth lens unit at the telephoto limit is larger than that at the wide-angle limit, and wherein focusing from an infinity in-focus condition to a close-object in-focus condition is performed by moving the fourth lens unit along the optical axis.

Abstract: A zoom lens includes a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having negative refracting power and a fifth lens group having negative refracting power in order from an object side, in which the lens groups move in magnification change from a wide angle end to a telephoto end such that a gap between the first lens group and the second lens group increases and a gap between the second lens group and the third lens group decreases, a negative lens group disposed closer to an image focusing side than a diaphragm among all lens groups is set as a focusing lens group, and the focusing lens group moves toward the image focusing side at focusing from infinity to a close object, the zoom lens satisfies a conditional expression.

Abstract: A zoom lens system comprising a plurality of lens units each being composed of at least one lens element, and comprising, in order from an object side to an image side, 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 positive optical power, and a fifth lens unit having negative optical power, wherein the first lens unit is composed of two or less lens elements, the third lens unit is composed of five or more lens elements, and the condition: 5.0<f1/f3<8.0 (f1: a focal length of the first lens unit, f3: a focal length of the third lens unit) is satisfied.

Abstract: A zoom lens includes, from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, an aperture stop, a fourth lens unit having positive refractive power, and a fifth lens unit having negative refractive power. The distance between adjacent lens units changes during zooming. The third lens unit includes at least one positive lens and further includes at least one negative lens at the image side of the positive lens. A focal length of the second lens unit, a focal length of the fifth lens unit, a combined focal length of lenses disposed at the object side of the aperture stop at a wide-angle end, and a combined focal length of lenses disposed at the image side of the aperture stop at the wide-angle end are suitably set.

Abstract: The zoom lens includes, in order from an object side to an image side: a first lens unit having a positive refractive power that does not move for zooming; a second lens unit having a negative refractive power that moves during zooming; at least one lens unit that moves during zooming; and a rear lens group including an aperture stop, wherein the rear lens group has a zooming rear lens unit that moves during zooming, and a refractive power of the rear lens group at a wide-angle end, a refractive power of the zooming rear lens unit, and a lateral magnification of the lens unit in the image side from the zooming rear lens unit, which is set at the wide-angle end and focuses on infinity, are appropriately set.

Abstract: A five-group zoom lens including, in order from the object side, positive, negative, negative, positive, and positive groups. The first group includes a negative meniscus lens with the concave surface toward the image side, a positive lens and a positive lens. The second group includes a negative lens with the image-side surface having an absolute value of curvature radius smaller than that of the object side surface, a biconcave lens, and a biconvex lens. The third group includes a negative lens with the object side surface having an absolute value of curvature radius smaller than that of the image-side surface, and is moved during focusing on a closer object. The fifth group includes a positive fifth-A group including a biconvex lens, and a negative fifth-B group including a biconcave lens and a biconvex lens, wherein condition expression (1) is satisfied: 0.22<fW/f1<0.27??(1).

Abstract: Embodiments are disclosed herein related to the construction of optical elements for depth sensor systems. One disclosed embodiment provides a wide-angle lens construction comprising a first, negative stage, and a second, positive stage positioned behind the first, negative stage along an optical axis of the lens construction. The second, positive stage further comprises a first positive lens substage, a second positive lens substage, a third positive lens substage, the second positive lens substage positioned between the first positive lens substage and the third positive lens substage.

Abstract: An imaging lens includes a first lens group having positive refractive power and a second lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens having positive refractive power, a second lens having positive refractive power, and a third lens having negative refractive power. The second lens group includes a fourth lens having positive refractive power, a fifth lens, and a sixth lens having negative refractive power. The first lens and second lens have specific focal lengths. The first to third lenses have specific Abbe's numbers.

Abstract: A zoom lens that includes, in order from an object side to an image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power, and when zooming from a wide angle position to a telephoto position, an interval between the first lens group and the second lens group decreases, an interval between the second lens group and the third lens group decreases, and an interval between the third lens group and the fourth lens group increases.

Abstract: A zoom lens includes, in order from an object side to an image side: a first lens group that has a positive refractive power; a second lens group that has a negative refractive power; a third lens group that has a positive refractive power; and a fourth lens group that has a positive refractive power. During zooming from a wide-angle end to a telephoto end, the first lens group is stationary relative to an imaging surface, and the second lens group is moved to the image side in an optical axis direction so as to decrease a space between the second lens group and the third lens group. The third lens group includes a positive lens, a negative lens, and a cemented lens. The zoom lens satisfies ?0.95<fg3_neg/fg3<?0.5. Here, fg3_neg is a focal length of the negative lens of the third lens group, and fg3 is a focal length of the third lens group.

Abstract: A zoom lens includes, sequentially from an enlargement conjugate side to a reduction conjugate side: a 1st lens unit having negative refractive power not moved during zooming; plural lens units that are moved during zooming; and a final lens unit having positive refractive power that is not moved during zooming. A final moving lens unit having positive refractive power and disposed nearest to the reduction conjugate side among the plural lens units that are moved during zooming is moved toward the enlargement conjugate side during zooming from a wide angle end to a telephoto end, and the final moving lens unit includes one or more cemented lenses, and the final moving lens unit includes one or more negative lenses and one or more positive lenses. Predetermined conditional expressions are satisfied to maintain wide angle of view and high image quality along the entire zoom range.

Abstract: The magnification of the variable magnification finder is switchable, and the finder includes a positive lens group, a negative lens group, and an eyepiece lens group in this order from an object side in a high magnification state. The positive lens group is retracted from an optical path of the variable magnification finder to the outside of the optical path and the negative lens group moves toward the object side when magnification is changed from the high magnification state to a low magnification state. The following conditional formula is satisfied when the focal length of the negative lens group is fN: ?15 mm<fN<?5 mm.

Abstract: A finder optical system includes, in the order from a display device side to an eye point side, a first lens group to increase a light beam height of a light beam bundle incident from a display device side and to emit the light beam bundle to the eye point side, and a second lens group having an image formation action.

Abstract: A zoom lens comprising, in order from the object side to the image side, a first lens unit having a positive refractive power which does not move for zooming, a plurality of lens units which move during zooming, and a rear lens unit having a positive refractive power which does not move for zooming, wherein the refractive index, the Abbe constant, the partial dispersion ratio and the focal length of the positive lens located closest to the image side among the positive lenses in the first lens unit and the focal length of the first lens unit, the focal length of the positive lens located closest to the image side among the positive lenses in the first lens unit, and the focal length of the first lens unit are appropriately set.

Abstract: A projection zoom lens essentially consists of a negative first lens group, a positive second lens group through the fourth lens group that move along the optical axis while changing magnification, a fifth lens group that moves while changing magnification, and a positive sixth lens group disposed in this order from the magnification side, wherein the projection zoom lens satisfies conditional formulas (1) and (2) below: 1.9<m4/fw??(1) 0.7<(m3+m4)/(m2+m3+m4+m5)??(2), where, mk (k=2 through 5) is the absolute value of movement of the k-th lens group while changing magnification from the wide angle end to the telephoto end, and fw: the focal length of the entire system at the wide angle end.

Abstract: A zoom lens including, in order from an object side, positive, negative, positive, positive, and positive lens units, or positive, negative, positive, positive, positive, and positive lens units. 1.5<L2fm/L2W<500; ?30<f3/f2<?3; and ?15<f1/f23W<?8 are satisfied, where fm=fw×(Z)1/2, fw represents a focal length of the entire system at a wide angle end, Z represents a zoom ratio, L2W represents an interval between a second and third lens units at the wide angle end, L2fm represents an interval between the second and third lens units at a zoom position at which an offaxial principal ray having a largest image height is highest farthest from an optical axis on a lens surface disposed on the most object side in the first lens unit in a zoom range from the wide angle end to the focal length fm, f1, f2 and f3 respectively represent focal lengths of the first, second, and third lens units, and f23W represents a combined focal length of the second and third lens unit at the wide angle end.

Abstract: A zoom lens includes, in order from the object side, a positive first unit, a zooming lens group constituted by at least two lens units having a zooming function and a function of correcting image plane variation with zooming, and a last lens unit disposed on the most image side having an imaging effect and not moving for zooming. The first unit includes a negative first sub unit not moving for focusing, a second sub unit moving during focusing, and a positive third sub unit not moving for focusing. The first sub unit is composed of one or more concave lenses, and the third sub unit is composed of one or more convex lenses. Of the first and third sub units, the refractive powers, the average Abbe constants and the paraxial converted beam heights at the telephoto end are appropriately set.

Abstract: A finder optical system includes an image inverter optical member and an eyepiece lens system. The eyepiece lens system includes a first lens element, a positive biconvex second lens element, and a meniscus third lens element having a concave surface on the eyepoint side, in that order from the object side. A diopter adjustment operation is performed by moving the second lens element along the optical axis. Conditions (1) and (2) are satisfied: ?0.2<f/f3<0.2??(1), and 2.15<f(L3n?1)/L3b<3.00??(2), wherein f designates the focal length of the entire the eyepiece lens system at a diopter of ?1, f3 designates the focal length of the third lens element, L3n designates the refractive index at the d-line of the third lens element, and L3b designates the radius of curvature of the surface on the eyepoint side of the third lens element.