I agree 100%. DxO Viewpoint attempts to correct volume anamorphosis by applying horizontal geometry correction (distortion) to the right and left edges of the image. At the elongation link I provided Lee Jay stated it pretty clear:
.......the only "right" way is to take a circular fisheye image and project it onto the inside of a hemisphere (and then put the observer in the middle). That's why they do that in the IMAX domes. Makes for a bit of an expensive monitor and print solution, however. But everything else is some sort of compromise.
For 2D projections (screen and print viewing) we have limitations. The best example being what you stated:
twenty_one wrote:
Don't ask me to quote the exact laws of physics, I would have to look it up, but intuitively it clicks with me. There's a reason wide angle lenses have this corner stretching in order to preserve straight lines. If there wasn't, they wouldn't.
That's why it's physically impossible to create a 180° panorama image with perfect rectilinear correction. The corners of the image would need to be at Infinity.