Abstract: An image processing method includes the steps of calculating, with respect to a processing-target pixel in an input image signal, a concentric aberration correction amount for concentric aberration that is a component of magnification chromatic aberration, the concentric aberration causing a color shift to occur in a concentric manner from the center of an image, calculating, with respect to the processing-target pixel, a uniform aberration correction amount for uniform aberration that is a component of magnification chromatic aberration, the uniform aberration causing a color shift direction and a color shift amount to uniformly occur on a whole image, and correcting a pixel value of the processing-target pixel on the basis of the calculated concentric aberration correction amount and the calculated uniform aberration correction amount.

Abstract: A zoom lens is provided, which includes a first lens group Gr1 having positive refractive power, a second lens group Gr2 having negative refractive power, which is movable in an optical axis direction mainly for zooming (varying power), a third lens group Gr3 having positive refractive power, a fourth lens group Gr4 having negative refractive power, which is movable in the optical axis direction for correcting fluctuations in focal position during zooming and for focusing, and a fifth lens group Gr5 having positive refractive power, which lens groups are arrayed in order from an object side, wherein the first lens group includes a concave lens, a convex lens, and a triple-cemented lens T1 in which a lens L6 made of special low-dispersion glass is sandwiched in the middle, which lenses are arrayed in order from the object side. Thereby, a range from a super wide-angle area to a super telephoto area can be covered with angles of view of not less than 67 degrees at a wide-angle end and not more than 1.

Abstract: There is provided a zoom lens having, in an order of an object-to-image direction, a first lens group having a positive refractive power and fixed with respect to an image plane; a second lens group having a negative refractive power; a third lens group having a positive refractive power and fixed with respect to an optical axis direction; a fourth lens group having a positive refractive power; and a fifth lens group having a positive refractive power and fixed with respect to the optical axis direction. The fifth lens group is composed of a fifth-a lens group having a negative refractive power; a fifth-b lens group having a positive refractive power; and a fifth-c lens group having a positive refractive power, arranged in the order of the object-to-image direction.

Abstract: There is provided a zoom lens having, in an order of an object-to-image direction, a first lens group having a positive refractive power and fixed with respect to an image plane; a second lens group having a negative refractive power; a third lens group having a positive refractive power and fixed with respect to an optical axis direction; a fourth lens group having a positive refractive power; and a fifth lens group having a positive refractive power and fixed with respect to the optical axis direction. The fifth lens group is composed of a fifth-a lens group having a negative refractive power; a fifth-b lens group having a positive refractive power; and a fifth-c lens group having a positive refractive power, arranged in the order of the object-to-image direction.

Abstract: A zoom lens with a reduced overall length having a color separating prism therein and a telecentric property with a first lens group (GI) having a positive refractive power and having a fixed position, a second lens group (GII) of the variable magnification type having a negative refractive power and having a position movable for magnification variation, a third lens group (GIII) having a positive refractive power and having a fixed position and a fourth lens group (GIV) having a positive refractive power and having a position variable for adjustment of a focal position upon magnification variation and upon focusing are disposed in order from an object side. At least one face of the two convex lenses in the fourth lens group is formed from an aspheric face.

Abstract: A zoom lens is provided, which includes a first lens group Gr1 having positive refractive power, a second lens group Gr2 having negative refractive power, which is movable in an optical axis direction mainly for zooming (varying power), a third lens group Gr3 having positive refractive power, a fourth lens group Gr4 having negative refractive power, which is movable in the optical axis direction for correcting fluctuations in focal position during zooming and for focusing, and a fifth lens group Gr5 having positive refractive power, which lens groups are arrayed in order from an object side, wherein the first lens group includes a concave lens, a convex lens, and a triple-cemented lens T1 in which a lens L6 made of special low-dispersion glass is sandwiched in the middle, which lenses are arrayed in order from the object side. Thereby, a range from a super wide-angle area to a super telephoto area can be covered with angles of view of not less than 67 degrees at a wide-angle end and not more than 1.

Abstract: A zoom lens comprising a first lens group having a positive refracting power and its position fixed, a second lens group having a negative refracting power and displacable mainly for magnification, a third lens group having a positive refracting power and its position fixed, and a fourth lens group having a positive refracting power and displacable mainly for correction of the focal position for magnification and focusing.

Abstract: An artificial vision lens system suitable for simulating a retinal image obtained when a subject wears eyeglass lenses. The artificial vision lens system 3 corresponding to an ocular optical system is designed based on optical constants of a paraxial area calculated from a Glustrand's precision simulated eye. The artificial vision lens system 3 comprises, in order from the object side, a front lens group 31 composed of lenses L.sub.1 and L.sub.2 and having negative refracting power, a stop 32, and rear lens group 33 composed of lenses L.sub.3 through L.sub.6 and having positive refracting power. Positions of the object side principal point and the turning point of the artificial vision lens system 3 may be set at positions suitable for simulating the eyeglass lens and the eyeball. An image (retinal image) of the artificial vision lens system 3 is imaged by a CCD 5.

Abstract: An artificial vision system which simulates a retinal image obtained when a subject views a standard measuring object by turning his eyeball with respect to an eyeglass lens. An artificial vision lens system corresponding to an ocular optical system and a CCD camera having a CCD plane corresponding to a retina are provided within an artificial vision camera. Rotary movement of the eyeball centering on its turning point with respect to an eyeglass lens is simulated by turning the artificial vision camera in the horizontal direction by a rotary stage and by turning the glass lens in the vertical direction by another rotary stage. Turning and parallel movement mechanisms are provided under a stage on which the lens and the artificial vision camera are mounted so that the artificial vision camera always points toward a predetermined position on the standard object as viewed through the lens.

Abstract: An apparatus for simulating a retinal image obtained when a lens is used with a human eye. The apparatus can simulate intraocular lenses, contact lenses or eyeglass lenses. When intraocular lenses are simulated, a lens system 31 comprises photographic lenses and an intraocular lens mounting section. The intraocular lens is held within one or more liquid containing sections provided in the intraocular lens mounting section. The relative position of the photographic lenses and the intraocular lens is set by making the paraxial object point distance of a front refracting face of the intraocular lens substantially equal that calculated when the intraocular lens replaces a crystalline lens of Glustrand's ocular model. When simulating contact or eyeglass lenses, a front face of a lens disposed nearest the object in lens system 31 has substantially the same radius of curvature as that of a human cornea, and a contact lens supporting base has a shape corresponding to the conjunctiva of the eye.

Abstract: An aspherical spectacle lens that has a pair of first and second refractive surfaces, one or both of which have an aspherical shape. In this lens, the first refractive surface and/or the second refractive surface is defined by the following equation: ##EQU1## where mi designates a real number which is not less than 2; n an integer which is not less than 1; X a length of a perpendicular drawn from a point, which is positioned on the aspherical surface and is located at a distance .rho. from an optical axis, to a meridional plane, which contacts the aspherical surface at a vertex thereof; C curvature at the vertex of the aspherical surface; .rho. a distance from the optical axis; k what is called a cone constant; and A.sub.mi what is called an aspherical-surface coefficient of .rho..sup.mi. Thus, there is provided an aspherical spectacle lens in which decentration aberration is small.