The amplitude transfer function for coherent imaging in the Fresnel approximation is derived. It is shown that this transfer function can solve problems in Fresnel diffraction that the more usual Fraunhofer approximation cannot. Because of its simple form, it allows for the formal solution of the aperture specification problem in diffractive optics by giving the complex optics transmission function in terms of a given object plane amplitude distribution and a desired image plane amplitude distribution. Two examples of this use are presented. Finally, the generalization of this transfer function to imaging in partially coherent and incoherent light follows easily.