Good Luck I had two duff 85mm, and my third is great at MFD but slightly out from distances over 20feet - I'm contemplating sending it off for a fix.
I tried two 50mm both were horrible and could not be micro-adjusted, just for the record the Canon 50mm on my 5d2 focuses quicker. I still hanker for that 50mm Sigma as the colours and bokeh are lovely, at least I have the 85mm.

