The 512×512 pixel phantom cell object used for our computational experiments (a). The object is the same pure-phase cell phantom used in a prior study (Hagemann & Salditt, 2017), so that one can compare directly with those results. The only difference is that we used the complex conjugate of the phantom so as to have positive rather than negative phase shifts, since X-ray phase is advanced rather than retarded in materials (Larsson et al., 1924). (b) The simulated experimental intensities for NFH with propagation by a distance corresponding to a per-pixel Fresnel number [equation (6)] of 10-3. (c) One of the far-field diffraction patterns at the center of the object. In fact, a set of far-field diffraction intensity patterns were simulated for a series k of different illumination or probe positions across the sample, which is the type of data set one obtains in FFP. In (d) and (e), we show one of the NFP recordings of the object and the phase map of the illumination function used.