Abstract: A zoom optical system includes three lens groups, arranged as follows from the object side: a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. The first lens group includes, arranged as follows along the optical axis, a lens element having negative refractive power, a prism for bending the optical axis, and a lens element having positive refractive power. The second and third lens groups are movable along the optical axis for zooming with only the third lens group reversing its direction of movement along the optical axis during zooming from the wide-angle end to the telephoto end. The third lens group includes a stop, a cemented lens component, and at least one aspheric surface that may be made of plastic. The first lens group also includes at least one aspheric surface.

Abstract: Disclosed is an illumination optical system having an imaging optical system for imaging a predetermined object plane upon an image plane, by use of light supplied from an integrator that functions to produce a plurality of light sources using light from a light source. In one preferred form of the invention, the imaging optical system includes, in an order from a light incidence side thereof, a first lens group having a positive power, a second lens group having a negative power, and a third lens group having a positive power, wherein the second lens group includes a concave lens at a light exit side thereof and wherein the third lens group includes a convex lens at a light entrance side thereof. The position of intersection between an optical axis of the imaging optical system and a principal ray of abaxial light is defined between the second lens group and the third lens group.

Abstract: Object is to provide an inner-focusing type zoom lens system carrying out focusing by moving a portion of a first lens group suitable for an auto-focus SLR camera. A zoom lens system includes, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. Upon zooming from a wide-angle end state to a telephoto end state, a distance between the first and the second lens groups increases, and a distance between the second and the third lens groups decreases. The first lens group is composed of, in order from the object, a 1A lens group G1A having positive refractive power, and a 1B lens group G1B having positive refractive power. Focusing from infinity to a close-range object is carried out by moving only the 1B lens group G1B to the object.

Abstract: A zooming lens apparatus including a first optical lens group having a positive refractive power, a second optical lens group having a negative refractive power, a third optical lens group having a positive refractive power, and a fourth optical lens group having a positive refractive power. The zooming lens apparatus also includes an aperture diaphragm arranged between the second and third optical lens group. When a scaling of the zooming lens system is changed from a wide-angle limit to a telescopic limit, the first optical lens group and the third optical lens group are moved in a first direction, and the fourth optical lens group is moved in a second direction opposite of the first direction. The zooming lens apparatus satisfies an inequality condition 0.60<m4T<0.85, where m4T represents an imaging magnification of the fourth optical lens group at the telescopic limit.

Abstract: To provide a zoom lens system having high optical performance by using a diffractive optical element, the system includes a first group having positive power, a second group having negative power, and a third group having positive power. When zooming from a wide-angle end state to a telephoto end state, a distance between the first group and the second group and a distance between the second group and the third group vary. The third group is composed of a front group having positive power locating to the object side of the largest space in the third group and a rear group having negative power locating to an image side of the space. The front group includes an aperture stop and a diffractive optical surface. An incident angle of a principal ray reaching the maximum image height to the diffractive optical surface is ten degrees or less. Given condition is satisfied.

Abstract: A third group of lenses is constructed by subsequently arranging those four lenses from an object side to an image side which include a positive lens, a cemented lens of a positive lens and a negative lens, and a positive lens, both of a surface of the third group of the lenses nearest to the object side and a surface of the third group of the lenses nearest to the image side are so aspheric that positive refractive power becomes gradually weaker as a location of the third group of the lenses departs from an optical axis; and a following conditional formula is satisfied: ?0.5<(Y? max/R34I)<0.0 where R34I is a curvature radius of the surface of the third group of the lenses nearest to the image side, and Y? max is a maximum image height.

Abstract: Provided is an automatic focusing method used by a digital image processing apparatus including a zoom lens moving in a moving range of a first guide bar and a focus lens moving in a moving range of a second guide bar disposed on an extension of the first guide bar. The method includes performing focusing while moving the zoom lens in a range from a zooming limit position in the first guide bar to a set zoom limit position, if a current photographing mode is a close-range photographing mode and a current position of the zoom lens is the zooming limit position.

Abstract: A lens device having a function of varying a magnification of the lens device and a function of focusing includes, in the order from an object side to an image side, a first lens unit which has a positive optical power and which is fixed during the variation of magnification, a second lens unit which has a negative optical power and which moves during the variation of magnification, and a third lens unit which has a positive optical power and which is fixed during the variation of magnification. The third lens unit includes a first lens sub-unit which is fixed during focusing, a second lens sub-unit which has a positive optical power and which moves during focusing, and a third lens sub-unit which has a positive optical power and which is fixed during focusing, in that order from the object side to the image side.

Abstract: The present invention includes, from the object side to the image plane side, an aperture stop with a predetermined diameter, a first lens with a positive refractive power and a bi-convex shape with convex surfaces facing the object side and the image plane side, a second lens being formed as a meniscus shape with a concave surface facing the object side having a negative refractive power, and a third lens being formed as a meniscus shape with a convex surface facing the object side having a positive refractive power. By having a positive refractive power for the first lens and third lens and a negative refractive power for the second lens, a suitable back focus can be maintained while reducing the total length of the lens system. The imaging lens is thin and compact and has superior optical properties suited for mobile cameras mounted in portable telephones and PDAs.

Abstract: A first group optical system having a positive refracting power, a second group optical system having a negative refracting power, and a third group optical system having a positive refracting power are sequentially arranged from an object side toward an image side. At least the first group optical system and the third group optical system move so that a distance between the first group optical system and the second group optical system becomes minimum at short focal-length side, and a distance between the second group optical system and the third group optical system becomes minimum at long focal-length side. The third group optical system includes a triplet lens formed with a negative lens, a positive lens, and a negative lens.

Abstract: A zoom lens assembly (10) compensates optically, as opposed to mechanically, for changes in temperature. In a preferred embodiment a difference in focus between WFOV and NFOV zoom lens positions, over temperature, is minimized such that any actual shift in focus falls within the depth of focus of the zoom lens assembly. The zoom lens assembly has, along an optical axis, first and third lens elements (12,16) that are made from a first material and that have a positive power, a second lens element (14) interposed between the first and third lens elements and movable along the optical axis between a WFOV and NFOV position. The second lens element has a negative power and is made of a second material. The materials are selected such that a change in refractive index for a change in temperature of the first material is less than a change in refractive index for a change in temperature of the second material.

Abstract: An optical apparatus is provided with a zoom optical system. The zoom optical system includes a lens unit located at the most object-side position and a moving lens unit with positive refracting power, located on the image side of the lens unit. The lens unit includes a single positive lens and the moving lens unit is simply moved toward the object side when the magnification of the zoom lens is changed in the range from a wide-angle position to a telephoto position so as to satisfy the following condition: 0.8<y07/(fw·tan ?07w)<0.96 where fw is the focal length of the entire system of the zoom lens at the wide-angle position, y07 is an image height expressed by 0.

Abstract: A zoom lens system with a new structure is disclosed which realizes high optical performance by appropriately setting the structure of each lens unit and using a material with anomalous dispersion in an appropriate lens unit. Specifically, according to several aspect herein disclosed, the zoom lens system includes, in order from an object side to an image side, lens units having a positive, a negative, and a positive optical powers in which the structure of each lens unit is specified or a third lens unit employs a lens element made of a material with anomalous dispersion.

Abstract: A zoom lens to form an image of an object with variable magnification between a shortest focal length and a longest focal length, is provided with a first lens group having a positive refracting power; a second lens group positioned closer to the image than the first lens group and having a negative refracting power; and a third lens group positioned closer to the image than the second lens group and having a positive refracting power. When the magnification is changed from the shortest focal length to the longest focal length, the third lens group is shifted toward the object and the first lens group and the second lens group are shifted in such a manner that a distance between the first lens group and the second lens group is increased and a distance between the second group and the third group is decreased. The third lens group comprises at least a single positive lens and at least a single negative lens. A variable magnification ratio of the zoom lens is four times or more.

Abstract: This specification discloses a zoom lens having good optical performance over the whole of an object distance from an infinity object to a super-close range object. This zoom lens system comprises, in order from the front to the rear, a first lens unit of positive optical power, a second lens unit of negative optical power, and a following lens component of positive optical power as a whole. During zooming, the first lens unit moves so that the interval between the first lens unit and the second lens unit may become great at the telephoto end relative to the wide angle end. At least one lens unit moves for focusing resulting from a change in an object distance, and the lens unit moving for the focusing is provided with a diffractive optical surface.

Abstract: An optical magnifier is provided. One general form of one example embodiment includes two lens elements, at least two aspheric surfaces, and at least one diffractive surface. Another general form of another example embodiment includes three lens elements, and at least three aspheric surfaces. At least two of the aspheric surfaces can be simple conics. The optical magnifier, suitable for use in an electronic display system, has an apparent field of view of at least +/?10 degrees; a magnification of at least 15×; a back focal length of at least 5 mm; and an eye relief greater than the effective focal length of the optical magnifier. The lens elements can be made from plastic.

Abstract: A large numerical aperture objective lens is disclosed having three lens groups. In order from the object side, these lens groups include: a first lens group of positive refractive power that is formed of two positive lens elements and an achromatic set of paired lens elements formed of a lens element of negative refractive power and a lens element of positive refractive power, respectively; a second lens group of negative refractive power; and a third lens group of positive refractive power, with the surface of the third lens group nearest the object side being convex. Specified conditions are satisfied in order to provide a compact, large numerical aperture objective lens having its aberrations favorably corrected as well as to correct for shifts of focus caused by expansion/contraction of the lens barrel with changes in temperature.

Abstract: A focusing method for a zoom lens system, including at least two lens groups, enables a portion of the zoom lens system to function as a focusing lens group over the entire focal length constituted by discrete focal length ranges. The portion of the zoom lens system, functioning as the focusing lens group, is changed to another portion thereof, in accordance with to the discrete focal length ranges.

Abstract: A single focus lens includes, in order from the object side: a glass first lens component of positive refractive power and with a convex surface on the object side; a diaphragm stop; a second lens component of plastic, a meniscus shape with its concave surface on the object side, and which includes at least one aspheric surface; and a third lens component of plastic, a meniscus shape with it convex surface on the object side, and which includes two aspheric surfaces. Each lens component may consist of a single lens element. Specified conditions are satisfied in order to reduce aberrations, to insure that the light rays at the image plane are substantially orthogonal to the image plane, and to insure that a sufficient back focus is provided so as to enable the insertion of other optical elements.

Abstract: A first group optical system having a positive refracting power, a second group optical system having a negative refracting power, and a third group optical system having a positive refracting power are sequentially arranged from an object side toward an image side. At least the first group optical system and the third group optical system move so that a distance between the first group optical system and the second group optical system becomes minimum at short focal-length side, and a distance between the second group optical system and the third group optical system becomes minimum at long focal-length side. The third group optical system includes a triplet lens formed with a negative lens, a positive lens, and a negative lens.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, and a positive third lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, the positive first lens group remains stationary, the negative second lens group moves toward the image, and the positive third lens group moves toward the object. The positive first lens group includes a first sub-lens group which is stationary and a second sub-lens group which functions as a focusing lens group.

Abstract: A zoom lens system includes a first to a third lens groups. Upon zooming, the distance between the first and second lens groups increases, the distance between the second and third lens groups decreases. Each lens group is positioned closest to the object at the long focal length extremity. The third lens group includes first and second sub-lens groups. The first sub-lens group with at least one aspherical surface is positioned at the object-side end a reference distance, and the negative second sub-lens group is positioned at the image-side end thereof. The zoom lens system satisfies the following conditions: 1.7<fw/f3<2.5 . . . (1); −0.5<fw/f3b<−0.2 . . . (2); −45<&Dgr;Iasp<−20 . . .

Abstract: Disclosed is a zoom lens system which uses a diffractive optical element such that high optical performance can be obtained over the overall power variation range. The zoom lens system includes a first lens unit having positive optical power, and a second lens unit having negative optical power and disposed on a rearward side of the first lens unit. A diffractive optical portion is provided on a cemented surface, which is convex toward a forward side, in the first lens unit or the second lens unit.

Abstract: The invention relates to a microscope zoom objective lens system having improved optical performance, and comprising a compact optical system with a zoom ratio of at least 3. The microscope zoom objective lens system comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power and a third lens group G3 having positive refractive power. For zooming from a low to a high magnification side, the second and third lens groups G2 and G3 move along the optical axis while the separation between the first lens group G1 and the second lens group G2 becomes wide and the separation between the second lens group G2 and the third lens group G3 becomes narrow. The first lens group G1 comprises at least one doublet having positive refractive power and consisting of a positive lens and a negative lens. The positive lens has an Abbe number defined by &ngr;>80.

Abstract: The object is to provide a zoom lens system with an angle of view 2&ohgr; of about 74.1° to 11.8°, a zoom ratio of about 6.6, ultimately small in diameter and compact, being composed of less number of elements, and having high cost performance and superb optical performance. The system includes, in order from an object, a first lens group having positive refractive power, a second lens group having negative refractive power, at least one lens group, and a lens group Gm having positive refractive power as a whole. Zooming is carried out by changing an air space between the first lens group and the second lens group. The lens group Gm consists of, in order from the object, a positive lens component having a convex surface facing to an image side and a negative lens component having a concave surface facing to the object side. Particular conditions are satisfied.

Abstract: The invention relates to a microscope zoom objective lens system having improved optical performance, and comprising a compact optical system with a zoom ratio of at least 3. The microscope zoom objective lens system comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power and a third lens group G3 having positive refractive power. For zooming from a low to a high magnification side, the second and third lens groups G2 and G3 move along the optical axis while the separation between the first lens group G1 and the second lens group G2 becomes wide and the separation between the second lens group G2 and the third lens group G3 becomes narrow. The first lens group G1 comprises at least one doublet having positive refractive power and consisting of a positive lens and a negative lens. The positive lens has an Abbe number defined by &ngr;>80.

Abstract: This specification discloses a zoom lens having good optical performance over the whole of an object distance from an infinity object to a super-close range object. This zoom lens system comprises, in order from the front to the rear, a first lens unit of positive optical power, a second lens unit of negative optical power, and a following lens component of positive optical power as a whole. During zooming, the first lens unit moves so that the interval between the first lens unit and the second lens unit may become great at the telephoto end relative to the wide angle end. At least one lens unit moves for focusing resulting from a change in an object distance, and the lens unit moving for the focusing is provided with a diffractive optical surface.

Abstract: A rear conversion lens, for attachment to the rear of a main lens, is formed of only three lens groups of positive, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element of negative meniscus shape with its convex surface on the object side, and a second lens element of positive refractive power that is biconvex. The second lens group is formed of a third lens element that is biconcave, and a fourth lens element of negative refractive power with a concave surface on the object side. The third lens group is formed of a fifth lens element that is biconvex, and a sixth lens element of negative meniscus shape with its convex surface on the image side. Various conditions are satisfied to facilitate ease of manufacture and to assure good optical performance.

Abstract: The invention relates to a compact two-group zoom optical system which has an angle of view of 70° or greater at the wide-angle end and satisfactory image-formation capability all over the zoom range while maintaining a zoom ratio of 3 or greater. The zoom optical system comprises a first lens group G1 having positive refracting power and a second lens group G2 having negative refracting power. For zooming from the wide-angle end to the telephoto end, the respective lens groups move toward the object side while the spacing between the first lens group G1 and the second lens group G2 becomes narrow. The first lens group G1 consists of a first lens unit U1 having negative refracting power, a second lens unit U2 having positive refracting power and a third lens unit U3 having positive refracting power. Each lens unit consists of a single lens or a doublet.

Abstract: A zoom lens comprises a first lens group having a positive focal length, a second lens group having a negative focal length, an aperture stop member, a third lens group having a positive focal length, disposed in the stated order from an object. The first lens group includes a 1-1 negative meniscus lens having a convex surface facing the object, a positive 1-2 lens having a surface having a large curvature facing the object and joined to the 1-1 lens, and a positive meniscus 1-3 lens having a convex surface facing the object, disposed in the stated order from the object. A reflection preventing part is formed on a surface at which the 1-1 lens and the 1-2 lens are joined.

Abstract: An optical system has the first, second, and third lens units from an object side. The first and third lens units have positive refractive powers. The second lens unit has a negative refractive power. The second lens unit moves toward an image side during focusing from an object at an infinite distance to an object at a finite distance. The second lens unit has a sub lens unit. The sub lens unit moves in a direction perpendicular to an optical axis to correct an image shake.

Abstract: A variable objective is disclosed with finite transmission length L from the object plane 0 to the image plane 0′, comprising three axially displaceable lens groups, wherein, successively in the imaging direction, a first lens group has positive refractive power, a second lens group has negative refractive power and the third lens group has positive refractive power. In a variable objective of the type mentioned above, the first lens group and third lens group are displaceable jointly while maintaining the same relative distance L2, wherein the distance L1+D1actual measured between the first lens group and the object plane 0 changes by the amount D1actual=0 . . . D1max, while the distance D2actual between the second lens group and the object plane 0 is subjected to a positively-guided nonlinear change.

Abstract: A zoom lens includes a lens unit A of negative refractive power, and a lens unit B of positive refractive power disposed on an image side of the lens unit A. The lens unit B includes two cemented lens components and consists of not more than five lens elements. Then, the separation between the lens unit A and the lens unit B varies during zooming.

Abstract: A rear conversion lens, for attachment to the rear of a main lens, is formed of only three lens groups of positive, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element of negative meniscus shape with its convex surface on the object side, and a second lens element of positive refractive power that is biconvex. The second lens group is formed of a third lens element that is biconcave, and a fourth lens element of negative refractive power with a concave surface on the object side. The third lens group is formed of a fifth lens element that is biconvex, and a sixth lens element of negative meniscus shape with its convex surface on the image side. Various conditions are satisfied to facilitate ease of manufacture and to assure good optical performance.

Abstract: A photographing lens system includes an aperture stop, a first lens group, a second lens group, and a third lens group, in this order from the object. The first lens group includes a positive first lens element, and a negative second lens element which is cemented to or separate from the positive first lens element. The second lens group only includes a positive third lens element having an aspherical surface formed on at least one refractive surface thereof. The third lens group only includes a negative fourth lens element having an aspherical surface formed on at least one refractive surface thereof.

Abstract: A zoom lens system includes a first lens group, a second lens group, and a third lens group. At least the first and third lens groups move along the optical axis for zooming. The second lens group includes at least one negative lens element, and the zoom lens system satisfies the following conditions: 0.65<fw/f1<0.80  (1) 1.73<N2n<1.85  (2) 0.15<X3/fw<0.21  (3) −0.05<X2/X1<0.10  (4) wherein fw designates the focal length of the entire zoom lens system; f1 designates the focal length of the first lens group; N2n designates the average refractive index of the negative lens elements in the second lens group; X3 designates the traveling distance of the third lens group; X2 designates the traveling distance of the second lens group; X1 designates the traveling distance of the first lens group.

Abstract: The invention provides a compact, low-cost zoom lens system comprising a positive lens group and a negative lens group. The system comprises a first lens group G1 having positive refracting power and a second lens group G2 having negative refracting power. The second lens group comprises, in order from an object side thereof, a positive lens 2-1, a negative lens 2-2 and a negative lens 2-3. The lens 2-1 is a plastic lens. The second lens group G2 further satisfies: 1.05≦f21/fT<5  (1) 3.8<f22/fG2<8  (2) Here f21 is the focal length of lens 2-1 in the second lens group, f22 is the focal length of lens component 2-2 in the second lens group, fT is the focal length of the zoom lens system, and fG2 is the composite focal length of the second lens group.

Abstract: An image stabilizing optical lens device including, in order from an object side to an image side of the image stabilizing optical lens device, a first lens unit having positive refractive power, a second lens unit having negative refractive power and being movable along an optical axis of the image stabilizing optical lens device to perform focusing, and a third lens unit having positive refractive power, the third lens unit including a front lens sub-unit having negative refractive power and being movable so as to be decentered with respect to the optical axis and a rear lens sub-unit having positive refractive power.

Abstract: In a short-focal-length side zooming range, a moveable sub-lens group of a zoom lens system is made stationary at one of the object-side and the image-side end. At the intermediate switching focal length, the moveable sub-lens group is moved to the other of the object-side and the image-side end.

Abstract: A zoom lens system for forming an image of an object on a solid state imaging device includes a first lens unit having a positive optical power and being movable in a zooming operation; a second lens unit having a negative optical power; and a third lens unit having a positive optical power. The system satisfies at least one the following conditions: 0.8<M1WM/M1MT<2.5; 0.2<&Dgr;&bgr;3/&Dgr;&bgr;2<1.0; 0.7<m1/Z<3.0; 1.0<img*R<15.0; 1.0<max(T1, T2, T3)<4; and 4.

Abstract: In order to provide an eyepiece lens which has a sufficiently long eye relief and a high magnification, there is provided an eyepiece lens for observing an image formed by an objective lens through an erect system, at least comprising a first lens group 4 having a positive refracting power and a second lens group 3 having a negative refracting power in this order from the side of an observer, and satisfying the following condition: −3<SF1<−1  (1) where SF1 indicates a shape factor of the first lens group 4, and SF indicates a shape factor of the lens group, which is defined by: SF=(Rs+RE)/(Rs−RE), where Rs indicates a radius of curvature of a lens surface which is closest to the object side and RE indicates a radius of curvature of a lens surface which is closest to the observer side.

Abstract: There is provided a zoom lens system of one aspect of the present invention includes, in order from an object side, a first lens unit of positive refractive power that doesn't move along an optical axis for zooming, a second lens unit of negative refractive power that moves along the optical axis for zooming, a third lens unit of positive refractive power that doesn't move along the optical axis for zooming, the third lens unit including, in order from the object side, a first lens subunit of positive refractive power consisting of one or two positive lens element facing to the object side a convex surface of refractive power that is stronger at the object side than an image side, and a second lens subunit including a cemented lens coupling a concave surface of a negative lens element of refractive power that is stronger at the image side than at the object side, with a convex surface of a positive lens element of refractive power that is stronger at the object side than at the image side, and a fourth lens u

Abstract: A lens having a long focal length that is suitable for photography with a large film size is disclosed having three lens groups of positive, negative, and positive refractive power, in order from the object side, as follows: a first lens group having a positive refractive power and formed of, in order from the object side, one or two positive lens element(s), a negative lens element, and a positive lens element; a second lens group having a negative refractive power and formed of, in order from the object side, a negative lens element and a positive lens element; and a third lens group having a positive refractive power and formed of, in order from the object side, a positive lens element, a negative lens element, and a positive lens element. Focusing is performed by moving the second lens group as one unit along the optical axis.

Abstract: A macro zoom lens system includes at least three lens groups, such as, a positive first lens group, a negative second lens group, and a positive third lens group, in this order from the object. Upon zooming, at least two lens groups are made moveable. On the other hand, upon focusing at any focal length in the focal-length range defined by the short focal length extremity and the long focal length extremity, any one of the lens groups other than the first lens group is made moveable. Furthermore, at the shortest object-to-image distance, an image magnification of more than ½ is obtained at the long focal length extremity.

Abstract: A zoom optical system suited for use in an electronic image pickup apparatus comprising a first negative lens unit, a second positive lens unit and a third positive lens unit, in which a magnification is changed from a wide position to a tele position by moving at least the first lens unit and the second lens unit so as to change an airspace between the first lens unit and the second lens unit and widen an airspace between the second lens unit and the third lens unit, the second lens unit comprises a biconvex lens element and a cemented meniscus lens component having a convex surface on the object side, and each lens unit has a small thickness.

Abstract: A telephoto lens system includes a positive first lens group, a negative second lens group and a positive third lens group.

Abstract: The invention relates to a zoom lens system of three-group construction, one lens for each group, which is less susceptible to aberration variations even upon zooming and can achieve entire-length reductions, large lens aperture and high zoom ratio. The zoom lens system comprises, in order from an object side thereof, a first lens group G1 consisting of one single lens formed of a homogeneous medium and having positive refracting power, a second lens group G2 consisting of one single lens formed of a homogeneous medium and having negative refracting power, and a third lens group G3 consisting of one single lens formed of a homogeneous medium and having positive refracting power. For zooming from a wide-angle end to a telephoto end of the zoom lens system, at least the second lens group G2 moves from the object side toward an image side of the zoom lens system.

Abstract: A zoom lens comprises a first lens group having a positive focal length, a second lens group having a negative focal length, an aperture stop member, a third lens group having a positive focal length, disposed in the stated order from an object. The first lens group includes a 1-1 negative meniscus lens having a convex surface facing the object, a positive 1-2 lens having a surface having a large curvature facing the object and joined to the 1-1 lens, and a positive meniscus 1-3 lens having a convex surface facing the object, disposed in the stated order from the object. A reflection preventing part is formed on a surface at which the 1-1 lens and the 1-2 lens are joined.

Abstract: A zoom lens system includes a positive first lens group, a negative second lens group, and a positive third lens group, in this order from the object. Zooming is performed by moving the second lens group and the third lens group, and the zoom lens system satisfies the following conditions: 0.0<Fw/f1<0.15  (1) 0.75<|f2/f3|<1.0  (2) 1.65<LD/Ft<2.25  (3) wherein Fw designates the focal length of the entire lens system at the short focal length extremity; Ft designates the focal length of the entire lens system at the long focal length extremity; f1 designates the focal length of the first lens group; f2 designates the focal length of the second lens group; f3 designates the focal length of the third lens group; and LD designates the distance, at the short focal length extremity, from the most object-side surface of the first lens group to the most image-side surface of the third lens group.

Abstract: A zoom lens system includes a plurality of lens groups, wherein a deflector which deflects the optical axis of said zoom lens system is positioned between lens groups which are made moveable upon zooming.