PSF and OTF comparison. a) Comparison of the expected point spread functions of the widefield, confocal (pinhole 0.3 and 0 AU) and OPRA system (m=0.5). Note that all these curves are normalized to one, whereas the OPRA point spread function is significantly brighter at the peak compared to the widefield system. b) Comparison of the respective optical transfer functions. The frequency axis is normalized to the Abbe limit and the transfer strength to a maximum of one.