Shape from focus is a method for the accurate measurement of the geometrical shape of objects. The measurement principle is the local focus search. Therefore, the method is suitable only for objects with a texture. The shape of the object is extracted from a series of 2D images. The 2D images are acquired while the distance of the measured object from the objective lens continuously changes. The longitudinal coordinate of the corresponding surface point is determined from the maximum of the focus measure function. The focus measure function expresses the quality of focus in a small image area and is calculated from the intensity values of individual pixels of a CCD camera by means of a focus measure operator. We present experimental results that demonstrate the capability of the proposed measurement method. The influence of illumination on the measurement uncertainty is studied. The comparison of the results for various focus measure operators and various light sources is presented.