I'd be surprised if anyone could really tell the difference between shots taken with a Bessa/Voigtlander kit vs a Leica kit. Quality rangefinders and primes are all quite good.
It's kind of like the Hasselblad vs Bronica debate. For most purposes people can't tell, but when the system is put to the test, the Hasselblad wins out. I think that Leica lenses are certainly in a class of their own and under some conditions (big enlargements, or high resolution requirement, or bokeh quality, or contrast), Leica's quality would show itself. But I do agree that for many shots one couldn't tell.
Scanning a 8x10 sheet of film at 1600 ppi produces a huge file and plenty of resolution. I have a 240mm Caltar that works great but is not quite as sharp as the Leica and Zeiss offerings in my DSLR kit.
If you take an 8x10 piece of sheet film, say Velvia, and cut out a 35mm section, it will be less detailed and less sharp than a 35mm Velvia slide (even if shot with a non-"elite" lens).
If you take a 35mm piece of film, or a "full frame" digital image and enlarge it to 8x10 inches, then it will be crushed in resolution by a native 8x10 image at capture size.
Simple optics, right? -- you need to enlarge the 35mm film roughly 8-fold to get an 8x10. So your 120 lp/mm Zeiss lens, which produced 120 lp/mm on the 35mm film, is now 15 lp/mm when enlarged to 8x10. Your 60 lp/mm Caltar is still 60 lp/mm at 8x10 because you haven't enlarged at all.
So if our measure is output / print resolution, then a 35mm will need to have 8-fold higher lens resolution than an 8x10 lens just to overcome the effect of enlargement.


I guess they just have a lot of historical expertise then.
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