Early BW films were mostly sensitive to the blue and green side of the spectrum. Only later did they become more sensitive to the entire visible spectrum (including the red zone, which we consider warmer). They were called panchromatic films (as opposed to earlier orthochromatic films).
There's some kind of emotional response people have to optical distortions which they don't have if they know it's from post-processing.
On an APC-C, at 135mm, difference between the maximum center resolution of a cheapish superzoom lens (Tamron 18-250mm), and a luxury prime lens (a Canon 135mm f/2) is ~10%. And neither perform best wide open (especially at the borders). The difference at the border is ~20%. The prime lens has other advantages (much better max apature, less distortion, less CA), but the sharpness of "bad" lenses is often underestimated.
My interest in photography tends to be periodic, with phases of intense interest, followed by droughts of inactivity. The last time I got back in to photography, I had already sold my old Canon A1 35mm camera, so I only had a Canon SD870IS point-and-shoot camera. I started out by digging around on the internet searching for the "best value" in camera gear.
I don't remember what triggered it, but I remember stopping to think, "If I want to take photos, what's stopping me from just taking this SD870 out and shooting?" After reflection, I decided that it didn't matter what other people thought of my gear. When/if I decided to post anything online, I'd just omit my gear information anyway.
So I went out, and I shot. As it turns out, I was really pleased with the results. I kept the 870 with me nearly all the time, so if I found myself driving back from out of town and saw some cool ship yard, I'd just stop and shoot it. I ended up getting some shots that I was really happy with.
It's often geeks (and genuinely good photographers) who shout the loudest that any camera with a decent sized sensor is fine. Yes, we love spec porn, but at least we know when it's a con.
- Chromatic aberrations. Most old lenses are not achromat or apochromat, so different wavelengths of light get refracted with different indices of refraction. In black-and-white photography, the colour fringes near the edges simply show up as being slightly blurry, so it's not as big of a deal as in modern colour photography.
- The plane of focus might not in fact planar, but may be curved due to the lens having a simple optical design with few elements. So when one focuses on the centre of the frame, the edges of the scene do not coincide with the plane of focus.
As for the claim that old lenses are sharper than modern lenses in the centre... perhaps it is true when comparing that lens to compact camera lenses and the such. But from my casual perusal of DSLR lens benchmarks, modern prime lenses are very, very sharp in the center and should certainly beat this lens - especially when stopped down. Modern DSLR prime lenses are often faster than f/2 wide open, whereas that old lens is f/6.8, yielding a deeper depth of field. But stopping the modern lens down to f/6.8 should result in superior resolution. Anyway, small cameras and cell phones can be less sharp due to diffraction effects on such a small scale.