Abstract: A relay optical system includes a cemented lens in which a first lens, a second lens, and a third lens having are cemented. The first lens is a meniscus lens which is adjacent to the third lens, and a dispersion and a partial dispersion ratio differ for the first lens and the third lens. In a rectangular coordinate system in which a horizontal axis is set to be ?dLA and a vertical axis is set to be ?gFLA, when a straight line expressed by ?gFLA=?×?dLA+?LA (where, ?=?0.00163) is set, ?gFLA and ?dLA of medium of the first lens are included in an area determined by the following conditional expression (1) and conditional expression (2), and the following conditional expression (3) is satisfied: 0.67??LA??(1) ?dLA<50??(2) ?1.4<mg<?0.6??(3).

Abstract: A relay optical system includes an object-side lens which is disposed nearest to an object, an image-side lens which is disposed nearest to an image, and a cemented lens having a positive refractive power. The object-side lens has a positive refractive power and is disposed such that a convex surface is directed toward an object side. The image-side lens has a positive refractive power and is disposed such that a convex surface is directed toward an image side. A plurality of the cemented lenses is disposed between the object-side lens and the image side lens and the following conditional expression (1) is satisfied: 0.04<Gce/Drel<0.4??(1) where, Gce denotes the smallest of intervals of adjacent cemented lenses, and Drel denotes a distance from an object plane up to an image plane of the relay optical system.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that determines an axial light beam, and one cemented lens, and an image pickup section which is disposed on an image side of the image forming optical system, and which has a surface which is not flat and is curved to be concave toward the image forming optical system, wherein the cemented lens includes in order from an object side, a first lens having a negative refractive power, a second lens, and a third lens having a positive refractive power.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that sets an axial light beam, and a diffracting optical surface disposed at a position different from a position where the aperture stop is disposed, and an imager which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system, wherein the diffracting optical surface satisfies the following conditional expression (1). 0.1<|DSD/TL|?1.

Abstract: An image pickup apparatus includes an image forming optical system having lens components and an image pickup unit, and the lens component is a lens having an object-side surface and an image-side surface that are in contact with air in an effective optical path, and the image forming optical system includes in order from an object side to an image side, an object-side lens component and an image-side lens component, and the image pickup unit has an image pickup surface curved to be concave toward the object side, and a surface nearest to the object of the object-side lens component has a concave shape portion which is concave shape toward the object side in a meridional direction, in at least an off-axis effective surface, and a surface nearest to the image of the image-side lens component is a curved surface.

Abstract: An image pickup apparatus includes an image forming optical system having an aperture stop, a first lens, and a second lens, and an imager having a light-receiving surface that is curved to be concave toward the image forming optical system, and a relative partial dispersion for a medium of the first lens differs from a relative partial dispersion for a medium of the second lens, and when a straight line indicated by ?gFLA=?×?dLA+?LA (where ?=?0.00163) has been set, ?gFLA and ?dLA for the medium of the first lens are included in both of an area determined by the following conditional expression (1) and an area determined by the following conditional expression (2), and the following conditional expression (3) is satisfied: 0.68<?LA??(1), ?dLA<50??(2), and 0<|f/Rimg|?1.5??(3).

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop and a plurality of lens components, and an image pickup section which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system. The image forming optical system includes a first lens component having a negative refractive power, a second lens component having a positive refractive power, and a third lens component having a positive refractive power. A shape of the first lens component is a meniscus shape, and a shape of the third lens component is a biconvex shape, and the following conditional expressions (1) and (2) are satisfied: 0.7<|PS×Rimg|<1.5??(1), and 0.7<|?out 90/?img 90|<1.5??(2).

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop and a plurality of lens components, and an image pickup section which has a light-receiving surface which is not flat but is curved to be concave toward the image forming optical system. The image forming optical system includes a first lens component having a negative refractive power, a second lens component having a positive refractive power, and a third lens component having a positive refractive power. In the first lens component, a lens surface on the object side is convex toward the object side, and in a lens surface on the object side of the second lens component, a part of an area is concave toward the object side. Moreover, the following conditional expression (1) is satisfied: 0.5<(R1L+R1R)/(R1L?R1R)<2.5??(1).

Abstract: A variable magnification optical system is an optical system in which, a magnification ratio varies from a lower magnification end to a high magnification end, and includes at least a first lens unit having a positive refractive power, which is disposed nearest to an object, and a second lens unit having a positive refractive power, which is disposed on an image side of the first lens unit. At the time of varying magnification, a distance between the first lens unit and the second lens unit changes, and the following conditional expression (1) is satisfied: 0<1/?HG1<1??(1), where, ?HG1 denotes an imaging magnification of the first lens unit at the high magnification end.

Abstract: A relay optical system includes a cemented lens in which a first lens, a second lens, and a third lens having are cemented. The first lens is a meniscus lens which is adjacent to the third lens, and a dispersion and a partial dispersion ratio differ for the first lens and the third lens. In a rectangular coordinate system in which a horizontal axis is let to be ?dLA and a vertical axis is let to be ?gFLA, when a straight line expressed by ?gFLA=?×?dLA+?LA (where, ?=?0.00163) is set, ?gFLA and ?dLA of medium of the first lens are included in an area determined by the following conditional expression (1) and conditional expression (2), and the following conditional expression (3) is satisfied: 0.67??LA??(1) ?dLA<50??(2) ?1.4<mg<?0.6??(3).

Abstract: A relay optical system includes an object-side lens which is disposed nearest to an object, an image-side lens which is disposed nearest to an image, and a cemented lens having a positive refractive power. The object-side lens has a positive refractive power and is disposed such that a convex surface is directed toward an object side. The image-side lens has a positive refractive power and is disposed such that a convex surface is directed toward an image side. A plurality of the cemented lenses is disposed between the object-side lens and the image side lens and the following conditional expression (1) is satisfied: 0.04<Gce/Drel<0.4??(1) where, Gce denotes the smallest of intervals of adjacent cemented lenses, and Drel denotes a distance from an object plane up to an image plane of the relay optical system.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop and a plurality of lens components, and an image pickup section which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system. The image forming optical system includes a first lens component having a negative refractive power, a second lens component having a positive refractive power, and a third lens component having a positive refractive power. A shape of the first lens component is a meniscus shape, and a shape of the third lens component is a biconvex shape, and the following conditional expressions (1) and (2) are satisfied: 0.7<|PS×Rimg|<1.5??(1), and 0.7<|?out 90/?img 90|<1.5??(2).

Abstract: A wide-angle optical system includes in order from an object side to an image side, a first lens having a negative refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, an aperture stop, a fourth lens having a positive refractive power, and a fifth lens. An object-side surface of the first lens is convex toward the object side, and the following conditional expression (1) is satisfied. 1.0<(R1L+R1R)/(R1L?R1R)?2.0??(1) where, R1L denotes a paraxial radius of curvature of the object-side surface of the first lens, and R1R denotes a paraxial radius of curvature of an image-side surface of the first lens.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that determines an axial light beam, and one cemented lens, and an image pickup section which is disposed on an image side of the image forming optical system, and which has a surface which is not flat and is curved to be concave toward the image forming optical system, wherein the cemented lens includes in order from an object side, a first lens having a negative refractive power, a second lens, and a third lens having a positive refractive power.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop and a plurality of lens components, and an image pickup section which has a light-receiving surface which is not flat but is curved to be concave toward the image forming optical system. The image forming optical system includes a first lens component having a negative refractive power, a second lens component having a positive refractive power, and a third lens component having a positive refractive power. In the first lens component, a lens surface on the object side is convex toward the object side, and in a lens surface on the object side of the second lens component, a part of an area is concave toward the object side. Moreover, the following conditional expression (1) is satisfied: 0.5<(R1L+R1R)/(R1L?R1R)<2.5 ??(1).

Abstract: An image pickup apparatus includes an image forming optical system having an aperture stop, a first lens, and a second lens, and an imager having a light-receiving surface that is curved to be concave toward the image forming optical system, and a relative partial dispersion for a medium of the first lens differs from a relative partial dispersion for a medium of the second lens, and when a straight line indicated by ?gFLA=?×?dLA+?LA (where ?=?0.00163) has been set, ?gFLA and ?dLA for the medium of the first lens are included in both of an area determined by the following conditional expression (1) and an area determined by the following conditional expression (2), and the following conditional expression (3) is satisfied: 0.68<?LA ??(1), ?dLA<50 ??(2), and 0<|f/Rimg|?1.5 ??(3).

Abstract: A zoom lens includes in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a negative refractive power, and includes an aperture stop which is disposed between the second lens unit and the fourth lens unit, and the first lens unit includes a negative lens and a plurality of positive lenses, and at the time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit widens, a distance between the second lens unit and the third lens unit narrows, and a distance between the third lens unit and the fourth lens unit changes, and the zoom lens satisfies predetermined conditional expressions.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that sets an axial light beam, and a diffracting optical surface disposed at a position different from a position where the aperture stop is disposed, and an imager which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system, wherein the diffracting optical surface satisfies the following conditional expression (1). 0.1<|DSD/TL|?1.

Abstract: A wide-angle optical system includes in order from an object side to an image side, a first lens having a negative refractive power, a second lens having a negative refractive power, a third lens having a positive refractive power, an aperture stop, a fourth lens having a positive refractive power, and a fifth lens. An object-side surface of the first lens is convex toward the object side, and the following conditional expression (1) is satisfied. 1.0<(R1L+R1R)/(R1L?R1R)?2.0??(1) where, R1L denotes a paraxial radius of curvature of the object-side surface of the first lens, and R1R denotes a paraxial radius of curvature of an image-side surface of the first lens.

Abstract: An image pickup apparatus includes an image forming optical system having lens components and an image pickup unit, and the lens component is a lens having an object-side surface and an image-side surface that are in contact with air in an effective optical path, and the image forming optical system includes in order from an object side to an image side, an object-side lens component and an image-side lens component, and the image pickup unit has an image pickup surface curved to be concave toward the object side, and a surface nearest to the object of the object-side lens component has a concave shape portion which is concave shape toward the object side in a meridional direction, in at least an off-axis effective surface, and a surface nearest to the image of the image-side lens component is a curved surface.