I would like to complete my kit with a good quality telephoto prime. I've the chance here in México to get a cheap Sigma 400mm f5.6 Minolta mount, green, beautiful. It could be my first legacy lens... But, after searching in several forums, I'm leaning toward the CANON FD 300mm f4 L, as the best IQ, relative small size, and well balanced (and tested) in my OMD + grip. What do you think? Must I consider another good option? It's easy manual focus with a 600/800mm equivalent? Budget under 400$. Thanks guys!