We present a shear interferometer that is based on an air wedge placed in the Fourier domain of a 4f-configuration as the shearing element. The two images are formed by the reflections from the front and reverse surfaces of the wedge. Due to a lateral displacement of the reflected beams in the Fourier domain, the interference pattern in the sensor domain is modulated by carrier fringes. Hence, the system is capable of single shot operation. The great advantage of this configuration over already existing shearing setups that make use of air wedges is that the shear can be set independently from the carrier modulation.