Sony just released new firmware to help resolve the backfocus issue on the PMW200 which has been seen on certain cameras. Travel and movent to the camera body can sometimes misalign the focus mechanism inside the camera. This firmware upgrade adds a feature to re-align it again. Its an easy upgrade and only takes a few minutes.
You close the LCD, set gain to H and simultaneously hold down the scroll wheel (select/set), MENY and CANCEL. This will bring up a deeper mainenence meny. Find FB Adjust and execute. Do with using a siemens focus star of something similar at about 10ft (3m) aimed directly at the target. The software will do this all by itself let you know when finished.
Doing this fixes the problem of the 2 cameras I tested to 95%. I can still see a slight slight focus shift in EXPANDED FOCUS while shooting wide open, but I think this is within specs on a lens like this. This sets my mind at ease and I would not hold back on buying this camera on account of any focus issue but I would certainly check the back focus with the meny setting above.