Testing Kowa 8Z with 90mm Leica R prime on a Canon 5dm3 body. Noticing an uncorrectable (via stretching or disqueezing) warp to the frame.
See image below, see how to the left of talent the window cabinet is slightly askew. See the door in the background off to the right of the frame is on a slight angle. See image below:
Any ideas on the cause of this and what to do? All lines should be straight - images within frame on same plane and leveled.