Abstract: An imaging apparatus includes an optical low-pass filter that includes first, second, third, and fourth optical anisotropic elements configured to separate an incident ray into a plurality of rays, and a retardation plate disposed between two optical anisotropic elements adjacent to each other among the first to fourth optical anisotropic elements, and an image sensor configured to photoelectrically convert an optical image formed by light that has passed the optical low-pass filter. A predetermined condition is satisfied.

Abstract: An imaging apparatus includes an optical low-pass filter that includes first, second, third, and fourth optical anisotropic elements configured to separate an incident ray into a plurality of rays, and a retardation plate disposed between two optical anisotropic elements adjacent to each other among the first to fourth optical anisotropic elements, and an image sensor configured to photoelectrically convert an optical image formed by light that has passed the optical low-pass filter. A predetermined condition is satisfied.

Abstract: The polarization acquisition apparatus is configured to allow an image capturing system including an interchangeable lens and an image capturing apparatus to perform image capturing using polarized light. The polarization acquisition apparatus includes a variable polarization axis element in which a direction of its polarization transmission axis is variable, a driver configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis, a first mount to which the image capturing apparatus is detachably attachable, and a second mount to which the interchangeable lens is detachably attachable. The driver is configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis to at least three directions when the image capturing is performed multiple times.

Abstract: An image pickup optical system includes an aperture stop, a first apodization filter disposed on an object side of the aperture stop, and a second apodization filter disposed on an image plane side of the aperture stop, each of the first apodization filter and the second apodization filter satisfies a predetermined condition, and a meridional light beam of a maximum angle of view has an optical path not involving at least one of a point of intersection between the optical axis and the first apodization filter and a point of intersection between the optical axis and the second apodization filter when an aperture size of the aperture stop is maximum.

Abstract: An image pickup optical system includes an aperture stop, a first apodization filter disposed on an object side of the aperture stop, and a second apodization filter disposed on an image plane side of the aperture stop, each of the first apodization filter and the second apodization filter satisfies a predetermined condition, and a meridional light beam of a maximum angle of view has an optical path not involving at least one of a point of intersection between the optical axis and the first apodization filter and a point of intersection between the optical axis and the second apodization filter when an aperture size of the aperture stop is maximum.

Abstract: An optical low pass filter includes a first birefringent plate, a second birefringent plate, a third birefringent plate, and a fourth birefringent plate. A conditional expression of 1.15<b/a<3 is satisfied, in a case where a separation width of an incident light ray in each of the first birefringent plate and the second birefringent plate is set to be a and a separation width of an incident light ray in each of the third birefringent plate and the fourth birefringent plate is set to be b.

Abstract: An image capturing apparatus includes first, second, third, and fourth image capturers. A protector is a portion projecting to an object side from a vertex of an optical surface closest to the object side of each of the two optical systems in the optical system between visual fields of the two image capturers among the first to fourth image capturers and is provided between visual fields of the first and third image capturers, between visual fields of the third and second image capturers, between visual fields of the second and fourth image capturers, and between visual fields of the first and fourth image capturer, and no protector is provided between the visual fields of the first and second image capturers and between the visual fields of the third and fourth image capturers.

Abstract: An optical low-pass filter is arranged on an object side than an image sensor in an image pickup apparatus and has an unevenness shape. The conditions of 5.0 ?m??z?80.0 ?m and 1.0?Ps/<Pf>?20.0 are satisfied where ?z represents a distance between the optical low-pass filter and the image sensor, Ps represents a pixel pitch of the image sensor, and <Pf> represents an average pitch of the unevenness shape.

Abstract: A control apparatus configured to control a lens apparatus having an operating unit for an optical zoom through a manual operation and an imaging apparatus configured to provide a digital zoom includes a first processor configured to determine a magnification of the digital zoom from a wide-angle end to a telephoto end based on information on a position of the operating unit, and a second processor configured to cause the imaging apparatus to perform the digital zoom based on an output from the first processor.

Abstract: The antireflection coating is a multi-layer film to be formed on a surface of a substrate. The film includes multiple layers including an uppermost layer most distant from the substrate among the multiple layers, and a lower layer including at least one layer other than the uppermost layer. A refractive index nm of the uppermost layer for a wavelength of ? (nm) satisfies a condition of 1.11?nm?1.3. An optical admittance Y of the lower layer is expressed by Y=a+ib, and a and b in the optical admittance satisfy conditions of (a?1.13)2+(b?0.24)2?0.452 for ?=430, (a?1.33)2+(b+0.05)2?0.252 for ?=900 and (a?1.14)2+(b+0.25)2?0.292 for ?=1800.

Abstract: An optical apparatus includes a first retardation plate giving a retardation between polarization components in slow and fast axis directions, a second retardation plate changing a relative retardation between polarization components in slow and fast axis directions, and a polarizer extracting a polarization component guided to the image pickup element. The first and second retardation plates, and the polarizer are disposed in order from an object side. The slow or fast axis direction of the first retardation plate is parallel to a polarization direction of the polarization component extracted by the polarizer. The slow or fast axis direction of the second retardation plate is inclined by 45 degrees with respect to the polarization direction. When a design wavelength is ?, a phase change amount being a difference between maximum and minimum values of the relative retardations is in a range from 2?/5 to 3?/5 both inclusive.

Abstract: A making method of random uneven data includes a step of making random uneven data by performing a filter operation in a real space using a filtering function with respect to random array data obtained using a random number or random array data obtained by randomly arranging a predetermined shape part.

Abstract: An optical element having antireflection function includes a substrate including a first relief structure, which includes a plurality of convexes and a plurality of concaves arrayed with a pitch of at most a half of a wavelength ?. A thin film layer including at least one thin film on the first relief structure. The at least one thin film each has a refractive index lower than a refractive index of the substrate. The optical element satisfies the following conditional expression: 1/4 ?h1/h0?2 and 1/5 ??D?2?, where h0 represents a first height difference between a top and a bottom of the first relief structure in a normal direction of a bottom plane of the first relief structure, h1 represents a second height difference between a top and a bottom of the second relief structure in the normal direction, D represents a maximum thickness of the thin film layer, and the wavelength ? is 550 nm.

Abstract: An optical low pass filter includes a first birefringent plate, a second birefringent plate, a third birefringent plate, and a fourth birefringent plate. A conditional expression of 1.15<b/a<3 is satisfied, in a case where a separation width of an incident light ray in each of the first birefringent plate and the second birefringent plate is set to be a and a separation width of an incident light ray in each of the third birefringent plate and the fourth birefringent plate is set to be b.

Abstract: Provided is an anti-reflection film, which is formed on substrate, the anti-reflection film having a laminated layer structure including, in order from the substrate: a first layer to a sixth layer each formed of a dielectric thin film; and a seventh layer formed by a wet process, in which the first to the sixth layers are formed of three kinds of mediums having different refractive indices from one another, and in which, when refractive indices of the three kinds of mediums at wavelength of 550 nm are defined as nL, nM, and nH, the first layer is formed of a medium having nM, the sixth layer is formed of a medium having nH, a layer formed of a medium having nL and a layer formed of a medium having off are spaced away from each other, and nL, nM, and nH are appropriately set.

Abstract: An optical apparatus includes a first retardation plate giving a retardation between polarization components in slow and fast axis directions, a second retardation plate changing a relative retardation between polarization components in slow and fast axis directions, and a polarizer extracting a polarization component guided to the image pickup element. The first and second retardation plates, and the polarizer are disposed in order from an object side. The slow or fast axis direction of the first retardation plate is parallel to a polarization direction of the polarization component extracted by the polarizer. The slow or fast axis direction of the second retardation plate is inclined by 45 degrees with respect to the polarization direction. When a design wavelength is ?, a phase change amount being a difference between maximum and minimum values of the relative retardations is in a range from 2?/5 to 3?/5 both inclusive.

Abstract: An anti-reflection film includes first through ninth layers. Regarding light having a wavelength of 550 nm, where the refractive indexes of the first through ninth layers are n1 through n9 respectively, the optical film thicknesses d1 through d9 (nm) respectively, and the maximum value of the difference in the refractive index between adjoining layers for layers 1 through 8 is ?n, the following conditions are satisfied. 1.60?n1?1.70, 15 nm?d1?140 nm, 2.00?n2?2.40, 20 nm?d2?120 nm, 1.60?n3?1.70, 11 nm?d3?70 nm, 2.00?n4?2.40, 20 nm?d4?165 nm, 1.60?n5?1.70, 15 nm?d5?45 nm, 2.00?n6?2.40, 90 nm?d6?175 nm, 1.60?n7?1.70, 50 nm?d7?110 nm, 2.00?n8?2.40, 20 nm?d8?50 nm, 1.20?n9?1.28, 140 nm?d9?160 nm, and 0.40??n?0.67.

Abstract: The antireflection coating is a multi-layer film to be formed on a surface of a substrate. The film includes multiple layers including an uppermost layer most distant from the substrate among the multiple layers, and a lower layer including at least one layer other than the uppermost layer. A refractive index nm of the uppermost layer for a wavelength of ? (nm) satisfies a condition of 1.11?nm?1.3. An optical admittance Y of the lower layer is expressed by Y=a+ib, and a and b in the optical admittance satisfy conditions of (a?1.13)2+(b?0.24)2?0.452 for ?=430, (a?1.33)2+(b+0.05)2?0.252 for ?=900 and (a?1.14)2+(b+0.25)2?0.292 for ?=1800.

Abstract: The polarization acquisition apparatus is configured to allow an image capturing system including an interchangeable lens and an image capturing apparatus to perform image capturing using polarized light. The polarization acquisition apparatus includes a variable polarization axis element in which a direction of its polarization transmission axis is variable, a driver configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis, a first mount to which the image capturing apparatus is detachably attachable, and a second mount to which the interchangeable lens is detachably attachable. The driver is configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis to at least three directions when the image capturing is performed multiple times.

Abstract: An image pickup optical system includes an aperture stop, a first apodization filter disposed on an object side of the aperture stop, and a second apodization filter disposed on an image plane side of the aperture stop, each of the first apodization filter and the second apodization filter satisfies a predetermined condition, and a meridional light beam of a maximum angle of view has an optical path not involving at least one of a point of intersection between the optical axis and the first apodization filter and a point of intersection between the optical axis and the second apodization filter when an aperture size of the aperture stop is maximum.