But I noticed one thing that seemed to me not acurate. I understand that the positions of the stars will be different when viewed from near a black hole, because the trajectory of their light was curved before reaching our virtual" eye. But I think the lens flares cannot be distorded so, because the processus that create them (diffraction on the camera objective) happens after the light passes near the black hole.
I know. But I can't make a proper effect for now - it is too hard. So this "unproper" effect is better than nothing for now.