Among many other old lenses, I have two Tamron Adaptall lenses (designed so you could fit a mount for whatever make of camera you were using). One that was praised highly in its day was the SP180 f2.5. The problem with it was its weight, even by the standards of modern Canon or Sony lenses. It is very dense so must have a lot of heavy glass inside. It received rave reviews for its sharpness and Bokeh when it came out, though I did not get it then. Mine was bought from Jessops in Birmingham New Street (yes, it used to be there). I went in attracted by the £15 price tag, but bought it even though they explained that was a mistake and it should have said £150, and they would withdraw it from sale. Only 3,000 were made, and the only one I can see on ebay right now is going for £779, though my guess is that is overpriced.
An Iris taken with it. From the shutter speeds, my guess is that the first is at f2.5 and the second stopped down to f8.