I have a chance to buy this lens for sub $50, should I go for it ? Didn't see it yet but the seller claims "like new". I don't have a FD-Nex adapter so I won't be able to test the IQ on Nex (testing lens operation should be easy enough without a camera). It offers extra 35mm (along with extra weight) to my MD 35-70/3.5 Macro, which is my most favorite lens for outside / not running. How does the IQ compare ?