If it is AF, then probably 90/2.8 ? The first MF version, which I own, is built like a tank. And contrast may be better than I thought : despite the cleaning done at the shop, and a further one by myself, I noticed yesterday (under strong light) that the front lens, while looking clean, was slightly milky. I suspect it got cleaned with one of those pre-impregnated towels like I bought long ago in a shop (a photographer, not a grocery) and indeed left some veiling behind, which is difficult to get rid of. Never again.
After using my lens pen again, it seems that I got it right now. We'll see if it makes a difference. Otherwise the lens (52B version) is known for its propensity to flare (coatings are just average), but it is more than usable.