Thanks for the info. I didn't know about the Nyquist limit, although now that you mention it, it sounds familiar.
To me, modern 35 mm film in a theater looks like it has about the resolution and acutance of the best 70 mm prints from 65 mm negatives of the past, although the projection doesn't seem to have the brightness of the old carbon-arc lamps. There were a few softer appearing 70 mm films back then like 2001: A Space Odyssey (people shots only, the man-apes and the space gear looked fine), 80 Days, and Oklahoma! (the latter two may have used inferior lenses, but the sense of depth was striking). The 70 mm equipped theaters I frequented often had seats that went right down to very near a large (sometimes curved) screen, so the size of the image on the beholder's retina was larger than is typical in 35 mm projection today, so I'm not sure of my subjective detail comparison.
My puzzlement is around some of the Blu-ray versions of the old large format films that don't do them justice. Lawrence does seem to be detailed enough, even though the home Blu-ray version is only about 2K (given the discussion in the early posts in this thread). Ben-Hur is an odd case. We hear that it was scanned at 6K, but while the faces are fine, the long shots are much blurrier than I remember in 70 mm or 35 mm, and they seem worse than in the Lawrence BD... but the grain is sharply reproduced and, sadly, larger and more apparent than in Lawrence.
