> the old lenses are very good on modern cameras up to around 18/24 M Pixels.

I have never seen this even with pretty old lenses. Maybe lack of sharpness but real loss of quality I have never seen

It depends on the modern camera, the old lenses are very good on modern cameras up to around 18/24 M Pixels.

If you use old lenses on cameras with sensors that are too dense, then you see the limitations produced by such a different technology.

Then, I'm not sure how to write it in English, but vintage lenses have a central centering, which doesn't get along too well with the focus of digital cameras