I wonder if a contributing factor to this perception that 70mm and IMAX has less distortion might be due to the lack of lens choices. It is my understanding, for instance, that only Panavision made anamorphic lenses for standard 70mm, and they only made a single set. Seeing Hateful Eight projected in 70mm, shot on Ben Hur anamorphic lenses, still looked really clean... so, with only spherical prime lenses and a single set of anamorphics from Panavision available, Its easy to see how such films have less visual distortion than a great deal of other productions that had more tools (and dear I say shortcuts?) available. It is also a nice novelty to view old family movies from the 1950s onward, shot on 70mm and viewing on a recently mastered Blu-ray, and think that it could have been shot yesterday. 70mm is indeed the gold standard.