skitron, how consistently does your Sigma 50/1.4 focus over different distances? I have the problem that my ("old") copy focuses well on near distances (within 5 meters, say), but inconsistently further away, which is extremely annoying because I think the lens is splendid optically (with lovely bokeh). On the other hand, I have tended to use it indoors mostly, which normally limits it to close distances, so it hasn't been a huge problem for me yet, but if there is a better AF performing version I would trade in an instant.
