Method for measuring the shape of a section of a semi-transparent object such as one section of a tooth, using a light source for generating light with a broadband spectrum in a device for generating a multifocal illumination pattern, a lens with a large chromatic aberration for imaging foci of the illumination pattern onto the object, and a detection device for determining the wavelength spectra of the foci confocally imaged onto the object via the lens, wherein a spectral peak position of each focus is determined from the respective wavelength spectrum, from which position the extent of the object in the direction of the imaging beam (Z coordinate) is calculated.