An analysis is presented of a shear interferometer based on double–exposure recording of holograms of the focused image of a mat screen with two successive Fourier transforms. It is shown both theoretically and experimentally that spatial filtration in the hologram plane enables control of the field of a lens or an objective . The spatial filtering in the far diffraction zone makes it possible to record the interference pattern characterizing the phase distortions introduced in the wave illuminating the mat screen by the aberrations of the illuminating optical system.