Comparison between theoretical phases and phases reconstructed by COFFEE for sine-like phases with an amplitude of 70 nm and three different spatial frequencies: (a) two cycles per pupil, (b) 3.5 cycles per pupil, and (c) 15 cycles per pupil. For each case, we show: (1) the PSF in the detector plane, (2) the theoretical phase map to reconstruct, (3) the phase map reconstructed by COFFEE, cropped by the Lyot stop, (4) the difference, cropped by the Lyot stop, between the theoretical phase map and the phase map reconstructed by COFFEE, and (5) the power spectral distribution (PSD) of the theoretical phase and the phase reconstructed by COFFEE. On these curves, the cutoff frequency of the FPM is indicated in grey, and the frequency of introduced sine phase in green.