A microscopic device for three-dimensional localization of point-like objects (30, 114) in a specimen, comprising: a detection optical system (36, 108) that images point-like objects (30, 114) arranged in an object space, each in the form of a three-dimensional focus light distribution, into an image space, characterized by a color separation apparatus that divides the light generated by the detection optical system (36, 108) for imaging the point-like objects (30, 114) into at least two separate light bundles whose light wavelengths lie in different wavelength regions, at least two detector units (146, 148) arranged in the image space, of which one detector unit receives the one of the two light bundles and the other detector unit receives the other of the two light bundles, each detector unit (146, 148) comprising a detection surface (38, 150, 152), arranged perpendicular to the incidence direction of the respective light bundle, for sensing light spots that each represent a planar section through the associated focus light distribution, an evaluation unit that, by evaluating the respective light spot sensed on the respective detection surface (38, 150, 152), ascertains a lateral x-y-position of the associated point-like object (30, 114) within an object plane parallel to a sharpness plane, and an axial z-position of the associated point-like object (30, 114) relative to the sharpness plane in the direction of an optical axis located perpendicular to the sharpness plane, the respective sharpness plane being a plane, located in the object space, that is optically conjugated with a detection plane which is located in the image space and in which the respective detection surface (38, 150, 152) is arranged, wherein at least one z-position correction value for at least one of the two wavelength regions is stored in the evaluation unit, which value indicates a longitudinal chromatic aberration of the detection optical system (36, 108) in that wavelength region, the evaluation unit ascertains the color of the respectively imaged point-like object (30, 114) on the basis of the ratio of the brightnesses of the light spots sensed by the two detection surfaces (150, 152) and belonging to that point-like object (30, 114), and assigns the ascertained color to the associated z-position correction value that indicates the longitudinal chromatic aberration for that color, the evaluation unit corrects the z-position, ascertained in the respective wavelength region, of the respective point-like object (30, 114) using the associated z-position correction value, and the sharpness planes allocated to the two detection surfaces are offset from one another in the object space. a detection optical system (36, 108) that images point-like objects (30, 114) arranged in an object space, each in the form of a three-dimensional focus light distribution, into an image space, characterized by a color separation apparatus that divides the light generated by the detection optical system (36, 108) for imaging the point-like objects (30, 114) into at least two separate light bundles whose light wavelengths lie in different wavelength regions, at least two detector units (146, 148) arranged in the image space, of which one detector unit receives the one of the two light bundles and the other detector unit receives the other of the two light bundles, each detector unit (146, 148) comprising a detection surface (38, 150, 152), arranged perpendicular to the incidence direction of the respective light bundle, for sensing light spots that each represent a planar section through the associated focus light distribution, an evaluation unit that, by evaluating the respective light spot sensed on the respective detection surface (38, 150, 152), ascertains a lateral x-y-position of the associated point-like object (30, 114) within an object plane parallel to a sharpness plane, and an axial z-position of the associated point-like object (30, 114) relative to the sharpness plane in the direction of an optical axis located perpendicular to the sharpness plane, the respective sharpness plane being a plane, located in the object space, that is optically conjugated with a detection plane which is located in the image space and in which the respective detection surface (38, 150, 152) is arranged, wherein at least one z-position correction value for at least one of the two wavelength regions is stored in the evaluation unit, which value indicates a longitudinal chromatic aberration of the detection optical system (36, 108) in that wavelength region, the evaluation unit ascertains the color of the respectively imaged point-like object (30, 114) on the basis of the ratio of the brightnesses of the light spots sensed by the two detection surfaces (150, 152) and belonging to that point-like object (30, 114), and assigns the ascertained color to the associated z-position correction value that indicates the longitudinal chromatic aberration for that color, the evaluation unit corrects the z-position, ascertained in the respective wavelength region, of the respective point-like object (30, 114) using the associated z-position correction value, and the sharpness planes allocated to the two detection surfaces are offset from one another in the object space.