An optical sensor for measuring at least one of a range, a position, and a profile of an object that is to be measured, the measured object emitting electromagnetic radiation due to the temperature of the object to be measured, and the sensor having a light source for illuminating the surface of the measured object and a detector for detecting the illuminating light reflected at the object to be measured, wherein with respect to the measurability even on the bodies that emit electromagnetic radiation, the light generated by the light source has a wavelength below the peak of the Planck radiation spectrum of the object that is to be measured. A corresponding method is specified.