I just walked away from a charity (thrift) shop with a Tamron 135mm f/2.5 Adaptall-2 lens for £12 (= about $18 US). I bought it more out of curiosity than any hope of it being a stellar performer, but wow! After some quick tests on my D800 it performs far beyond anything I expected of it. LoCA fringing is very low at maximum aperture and it puts most modern lenses to shame in this respect. Central sharpness and contrast looks very good at f/4 and smaller, plus it focuses to just under 1.2 metres. When the weather improves I'll check out its resistance to flare, etc. but I think I've got a keeper. The Tamron model number is 03B, and it was only produced for 5 years between 1979 and 1984. For a lens at least 30 years old it's in great mechanical and optical shape. Focus is smooth and the aperture works snappily, just as it should. No marks on the glass at all. The mechanical condition is a tribute to the build quality of Tamron lenses of that era. Got any good bargain glass lately? Share your best (or worst) experience.