Abstract: A compact zoom lens system having excellent optical performance. The zoom lens system includes a first lens unit of negative optical power, a second lens unit of positive optical power, a third lens unit of positive optical power, and an F-number defining member. The second lens unit is disposed on the image side of the first lens unit and includes a lens element disposed closest to the object side. The lens element has a rim, a surface on the object side and having a vertex, and an intersection point defined by an intersection between the surface and the rim. The third lens unit is disposed on the image side of the second lens unit. The F-number defining member is disposed along the optical axis between the vertex and the intersection point. Spaces between the first, second and third lens units vary during zooming.

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

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

Abstract: A compact zoom lens system having excellent optical performance. The zoom lens system includes a first lens unit of negative optical power, a second lens unit of positive optical power, a third lens unit of positive optical power, and an F-number defining member. The second lens unit is disposed on the image side of the first lens unit and includes a lens element disposed closest to the object side. The lens element has a rim, a surface on the object side and having a vertex, and an intersection point defined by an intersection between the surface and the rim. The third lens unit is disposed on the image side of the second lens unit. The F-number defining member is disposed along the optical axis between the vertex and the intersection point. Spaces between the first, second and third lens units vary during zooming.

Abstract: A compact zoom lens system having excellent optical performance. The zoom lens system includes a first lens unit of negative optical power, a second lens unit of positive optical power, a third lens unit of positive optical power, and an F-number defining member. The second lens unit is disposed on the image side of the first lens unit and includes a lens element disposed closest to the object side. The lens element has a rim, a surface on the object side and having a vertex, and an intersection point defined by an intersection between the surface and the rim. The third lens unit is disposed on the image side of the second lens unit. The F-number defining member is disposed along the optical axis between the vertex and the intersection point. Spaces between the first, second and third lens units vary during zooming.

Abstract: The present invention has as its object to obtain a zoom lens having a high variable power ratio, and having high optical performance which can sufficiently cope with even the use, for example, of a solid state image pickup element having a wide angle of field. In a zoom lens having, in succession from an object side to an image side, a first lens unit L1 of negative optical power, a second lens unit L2 of positive optical power and a third lens unit L3 of positive optical power, wherein the interval between adjacent ones of the lens units is changed to thereby effect focusing, the first lens unit has a negative lens and a positive lens, the second lens unit has a positive lens and a negative lens, the third lens unit has a positive lens, and the object side and image side surfaces of the negative lens G11 of the first lens unit which is most adjacent to the object side are of an aspherical shape.

Abstract: At least one exemplary embodiment is directed to an optical system which includes a compound optical element including a lens element and a resin layer having different optical characteristics and having an aspherical interface therebetween. When Rref is a reference radius of curvature of the interface within an effective diameter, L is a distance from a diaphragm, ndg and ?dg are a refractive index and an Abbe number, respectively, of a material of the lens element at the d-line, and ndj and ?dj are a refractive index and an Abbe number, respectively, of a material of the resin layer at the d-line, the following expressions are satisfied: ?1.5<Rref/L<?0.3 one of 0.1<|ndg?ndj| and 5<|?dg??dj|.

Abstract: The present invention has as its object to obtain a zoom lens having a high variable power ratio, and having high optical performance which can sufficiently cope with even the use, for example, of a solid state image pickup element having a wide angle of field. In a zoom lens having, in succession from an object side to an image side, a first lens unit L1 of negative optical power, a second lens unit L2 of positive optical power and a third lens unit L3 of positive optical power, wherein the interval between adjacent ones of the lens units is changed to thereby effect focusing, the first lens unit has a negative lens and a positive lens, the second lens unit has a positive lens and a negative lens, the third lens unit has a positive lens, and the object side and image side surfaces of the negative lens G11 of the first lens unit which is most adjacent to the object side are of an aspherical shape.

Abstract: A zoom lens, comprising, in order from an object side to an image side: (a) a first lens unit of negative optical power; (b) a second lens unit of positive optical power; and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied during zooming, and wherein, during zooming from a wide-angle end to a telephoto end, the first lens unit moves so that its motion comprises (a) moving toward the image side and (b) moving thereafter toward the object side, and the third lens unit moves so that its motion comprises (a) moving toward the image side and (b) moving thereafter toward the object side.

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

Abstract: At least one exemplary embodiment is directed to a zoom lens system which includes, in order from an object side to an image side a first lens unit having negative optical power, a second lens unit having positive optical power, and a third lens unit having positive optical power. In zooming, a distance between the first lens unit and the second lens unit and a distance between the second lens unit and the third lens unit are changed.

Abstract: At least one exemplary embodiment is directed to an optical system which includes a compound optical element including a lens element and a resin layer having different optical characteristics and having an aspherical interface therebetween. When Rref is a reference radius of curvature of the interface within an effective diameter, L is a distance from a diaphragm, ndg and ?dg are a refractive index and an Abbe number, respectively, of a material of the lens element at the d-line, and ndj and ?dj are a refractive index and an Abbe number, respectively, of a material of the resin layer at the d-line, the following expressions are satisfied: ?1.5<Rref/L<?0.3 one of 0.1<|ndg?ndj| and 5<|?dg??dj|.

Abstract: The present invention has as its object to obtain a zoom lens having a high variable power ratio, and having high optical performance which can sufficiently cope with even the use, for example, of a solid state image pickup element having a wide angle of field. In a zoom lens having, in succession from an object side to an image side, a first lens unit L1 of negative optical power, a second lens unit L2 of positive optical power and a third lens unit L3 of positive optical power, wherein the interval between adjacent ones of the lens units is changed to thereby effect focusing, the first lens unit has a negative lens and a positive lens, the second lens unit has a positive lens and a negative lens, the third lens unit has a positive lens, and the object side and image side surfaces of the negative lens G11 of the first lens unit which is most adjacent to the object side are of an aspherical shape.

Abstract: A zoom lens, comprising, in order from an object side to an image side: (a) a first lens unit of negative optical power; (b) a second lens unit of positive optical power; and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied during zooming, and wherein, during zooming from a wide-angle end to a telephoto end, the first lens unit moves so that its motion comprises (a) moving toward the image side and (b) moving thereafter toward the object side, and the third lens unit moves so that its motion comprises (a) moving toward the image side and (b) moving thereafter toward the object side.

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

Abstract: A zoom lens, including, in order from an object side to an image side (a) a first lens unit of negative optical power, (b) a second lens unit of positive optical power, and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied to effect variation of magnification, and wherein, during the variation of magnification from a wide-angle end to a telephoto end with an infinitely distant object focused on, the third lens unit moves monotonically toward the image side or moves with a locus convex toward the image side.

Abstract: A zoom lens, including, in order from an object side to an image side (a) a first lens unit of negative optical power, (b) a second lens unit of positive optical power, and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied to effect variation of magnification, and wherein the zoom lens satisfies the following conditions: ndp3<1.5 and vdp3>70.0, where ndp3 and vdp3 are a refractive index and Abbe number, respectively, of material of the positive lens in the third lens unit.

Abstract: At least one exemplary embodiment is directed to a zoom lens system which includes, in order from an object side to an image side a first lens unit having negative optical power, a second lens unit having positive optical power, and a third lens unit having positive optical power. In zooming, a distance between the first lens unit and the second lens unit and a distance between the second lens unit and the third lens unit are changed.

Abstract: This application discloses a lens system comprising in order from an object side to an image side: an aperture stop; a first lens element, having a positive optical power; and a second lens element, having a negative optical power. By setting the shapes of the respective lens elements and the materials making up the respective lens elements so as to meet predetermined conditions in such a lens system, a lens system of a compact size which provides good optical performance is realized while securing telecentric characteristics.

Abstract: A zoom lens, including, in order from an object side to an image side (a) a first lens unit of negative optical power, (b) a second lens unit of positive optical power, and (c) a third lens unit of positive optical power, wherein a separation between the first lens unit and the second lens unit and a separation between the second lens unit and the third lens unit are varied to effect variation of magnification, and wherein, during the variation of magnification from a wide-angle end to a telephoto end with an infinitely distant object focused on, the third lens unit moves monotonically toward the image side or moves with a locus convex toward the image side.