Geometrical distortion of the pupil between the SLM and the ZELDA WFS. Left plot: full pixel displacement between the introduced Gaussian spots and their measured positions, with a scale multiplied by four. Center plot: displacement after subtracting the C component, again with a scale multiplied by four. Right plot: final residual displacement after correction of the measured positions, this time with a scale multiplied by 40. The black circles represent the pupil footprint.