Abstract: A single focal length imaging optical system, in order from an object side to an image side, comprising: a front unit composed of a plurality of lens elements; an aperture diaphragm; and a rear unit composed of a plurality of lens elements, wherein the front unit, in order from the object side to the image side, includes a lens element having negative optical power, a lens element having negative optical power, and a lens element having positive optical power, and includes a lens element having positive optical power and placed closest to the image side, and the rear unit includes a focusing lens unit which is composed of at least one lens element and moves along an optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and a lens element having negative optical power and placed closest to the image side.

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 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 system comprising: a positive first lens unit composed of three or more lens elements; a negative second lens unit; a positive third lens unit; a negative fourth lens unit; and a positive fifth lens unit, wherein at least the first, second and third lens units move with respect to an image surface in zooming, a focusing lens unit, which moves with respect to the image surface in focusing and is composed of one lens element, is provided, and the conditions: 3.2<LG3/(fT×tan(?T)) and 0.3<fG1/fT<0.9 (LG3: optical axial thickness of third lens unit, fT: focal length of zoom lens system at telephoto limit, ?T: half view angle at telephoto limit, fG1: focal length of first lens unit) are satisfied.

Abstract: A zoom lens system, in order from an object side to an image side, comprising a positive first lens unit, a negative second lens unit, a positive third lens unit, and a positive fourth lens unit, wherein the first lens unit is composed of a cemented lens element of one object side negative lens element and one image side positive lens element, the fourth lens unit is composed of one lens element, in zooming, the first to fourth lens units are individually moved along an optical axis so that air spaces between the respective lens units vary for magnification change, and the conditions: vdL12<43.50 and fT/fW?6.0 (vdL12: an Abbe number of the positive lens element in the first lens unit, fT and fW: focal lengths of the entire system at a telephoto limit and a wide-angle limit) are satisfied; an imaging device; and a camera.

Abstract: It has conventionally been difficult to reduce the size of a fast lens system having an F number of about 1.4 to 2.4. In a lens system of the present invention, a positive lens element is disposed closest to an object side. A diaphragm is disposed in a widest air space in the lens system. The lens system of the present invention satisfies the following conditions: 0.05<L_1/L—TH<0.21 1.5<L—TH/Y<8 where L_1 is an interval from a lens surface located closest to the object side to a lens surface located on the object side relative to the diaphragm; L_TH is an interval from the lens surface located closest to the object side to a lens surface located closest to an image side; and Y is a maximum image height.

Abstract: A zoom lens system comprising: a positive first lens unit; a negative second lens unit; a positive third lens unit; a fourth lens unit; and at least one subsequent lens unit, wherein the subsequent lens unit(s) includes a negative lens unit, the first and third lens units are respectively composed of two or less lens elements and four or more lens elements, the first and second lens units move along an optical axis in zooming, and the conditions: 0.0<LGmax/LG2<1.5, 0.2<|f2/fW|, and 0.1<|fe/f2| (LGmax: a maximum value of an axial thickness of the subsequent lens unit(s), LG2: an axial thickness of the second lens unit, fW, f2, and fe: focal lengths of the entire system at a wide-angle limit, the second lens unit, and a negative lens unit located closest to the image side) are satisfied.

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; and at least one subsequent lens unit, wherein the subsequent lens unit(s) includes a lens unit having negative optical power, the first lens unit is composed of two or less lens elements, the third lens unit is composed of four or more lens elements, the first lens unit and the second lens unit move along an optical axis in zooming, and the condition: 0<|fW/fe<2 (fe: a focal length of a lens unit having negative optical power and located closest to the image side in the entire system, fW: a focal length of the entire system at a wide-angle limit) is satisfied.

Abstract: It has conventionally been difficult to reduce the size of a fast lens system having an F number of about 1.4 to 2.4. In a lens system of the present invention, a positive lens element is disposed closest to an object side. A diaphragm is disposed in a widest air space in the lens system. The lens system of the present invention satisfies the following conditions: 0.05<L_1/L—TH<0.21 1.5<L—TH/Y<8 where L_1 is an interval from a lens surface located closest to the object side to a lens surface located on the object side relative to the diaphragm; L_TH is an interval from the lens surface located closest to the object side to a lens surface located closest to an image side; and Y is a maximum image height.

Abstract: A zoom lens system comprising: a front unit having negative optical power as a whole and including a first lens unit located closest to the object side; and a rear unit having positive optical power as a whole, wherein at least the front unit moves along an optical axis in zooming, the first lens unit is composed of at most three lens elements, the rear unit includes a lens unit having an aperture diaphragm between lens elements, an air space between which is not varied in zooming, a sub lens unit comprising a part of a lens unit constituting the rear unit moves in a direction perpendicular to the optical axis, and the condition: 0.1<BF/fW<2.0 (?W>72°, FNOW<2.9, BF is a back focal length of the entire system at a wide-angle limit, fW is a focal length of the entire system at a wide-angle limit, ?W is a view angle at a wide-angle limit, FNOW is an F-number at a wide-angle limit) is satisfied; an imaging device; and a camera are provided.

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, and subsequent lens units including a fourth lens unit having optical power, wherein any one of the first lens unit, the second lens unit, the third lens unit, and the subsequent lens units includes a lens element having a reflecting surface that bends a light beam incident from an object, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit and the third lens unit do not move along an optical axis, and wherein the condition is satisfied: 1.42<nd4ave<1.58 (nd4ave is an average of refractive indices to the d-line of the lens elements constituting the fourth lens unit), an imaging device and a camera are provided.

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 the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming, the first to the fourth lens units are moved individually along an optical axis such that air spaces should vary, so that variable magnification is achieved, and wherein the conditions are satisfied: tan 2?W×m2W??1.78, tan 2?W×|fG2|/fG1?1.25, ?W?37 and fT/fW?10 (m2W is a lateral magnification of the second lens unit at a wide-angle limit, fG1 and fG2 are composite focal lengths of the first and the second lens units, ?W is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system respectively at a telephoto limit and at a wide-angle limit), an imaging device and a camera are provided.

Abstract: A zoom lens system, in order from an object side to an image side, comprising a positive first lens unit, a negative second lens unit, a positive third lens unit, and a positive fourth lens unit, wherein the first lens unit is composed of a cemented lens element of one object side negative lens element and one image side positive lens element, the fourth lens unit is composed of one lens element, in zooming, the first to fourth lens units are individually moved along an optical axis so that air spaces between the respective lens units vary for magnification change, and the conditions: vdL12<43.50 and fT/fW?6.0 (vdL12: an Abbe number of the positive lens element in the first lens unit, fT and fW: focal lengths of the entire system at a telephoto limit and a wide-angle limit) are satisfied; an imaging device; and a camera.

Abstract: A zoom lens system comprising a plurality of lens units including, in order from an object side to an image side, at least a positive first lens unit, a negative second lens unit, and a positive third lens unit, wherein any one of the plurality of lens units includes a lens element having a reflecting surface that bends a light beam incident from an object, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit and the third lens unit do not move along an optical axis, and the conditions: 4.25<?(fW×fT)/tG2<10.00 and fT/fW>2.5 (tG2: a thickness of the second lens unit, fT and fW: focal lengths of the entire system at a telephoto limit and a wide-angle limit) are satisfied; an imaging device; and a camera.

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 the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming, the first to the fourth lens units are moved individually along an optical axis such that air spaces should vary, so that variable magnification is achieved, and wherein the conditions are satisfied: 5.50?fG1/fW?7.92, ?W?35 and fT/fW?10 (fG1 is a composite focal length of the first lens unit, ?W is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system respectively at a telephoto limit and at a wide-angle limit), an imaging device and a camera are provided.

Abstract: A zoom lens system comprising: a front unit having negative optical power as a whole and including a first lens unit located closest to the object side; and a rear unit having positive optical power as a whole, wherein at least the front unit moves along an optical axis in zooming, the first lens unit is composed of at most three lens elements, the rear unit includes a lens unit having an aperture diaphragm between lens elements, an air space between which is not varied in zooming, a sub lens unit comprising a part of a lens unit constituting the rear unit moves in a direction perpendicular to the optical axis, and the condition: 0.1<BF/fW<2.0 (?W>72°, FNOW<2.9, BF is a back focal length of the entire system at a wide-angle limit, fW is a focal length of the entire system at a wide-angle limit, ?W is a view angle at a wide-angle limit, FNOW is an F-number at a wide-angle limit) is satisfied; an imaging device; and a camera are provided.

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 the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming, the first to the fourth lens units are moved individually along an optical axis such that air spaces should vary, so that variable magnification is achieved, and wherein the conditions are satisfied: 2.00?D/fW?4.68, ?W?35 and fT/fW?10 (D is a total of an optical axial thickness of each lens unit, ?W is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system respectively at a telephoto limit and at a wide-angle limit), an imaging device and a camera are provided.

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, and subsequent lens units including a fourth lens unit having optical power, wherein any one of the first lens unit, the second lens unit, the third lens unit, and the subsequent lens units includes a lens element having a reflecting surface that bends a light beam incident from an object, wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit and the third lens unit do not move along an optical axis, and wherein the condition is satisfied: 1.42<nd4ave<1.58 (nd4ave is an average of refractive indices to the d-line of the lens elements constituting the fourth lens unit), an imaging device and a camera are provided.

Abstract: It has conventionally been difficult to reduce the size of a fast lens system having an F number of about 1.4 to 2.4. In a lens system of the present invention, a positive lens element is disposed closest to an object side. A diaphragm is disposed in a widest air space in the lens system. The lens system of the present invention satisfies the following conditions: 0.05<L_1/L—TH<0.21 1.5<L—TH/Y<8 where L_1 is an interval from a lens surface located closest to the object side to a lens surface located on the object side relative to the diaphragm; L_TH is an interval from the lens surface located closest to the object side to a lens surface located closest to an image side; and Y is a maximum image height.

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 the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming, the first to the fourth lens units are moved individually along an optical axis such that air spaces should vary, so that variable magnification is achieved, and wherein the conditions are satisfied: 5.50?fG1/fW?7.92, ?W?35 and fT/fW?10 (fG1 is a composite focal length of the first lens unit, ?W is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system respectively at a telephoto limit and at a wide-angle limit), an imaging device and a camera are provided.