[stoppingdown]

Got it. The day was dull, grey and a bit rainy, so I couldn't run a full test — but a quick handheld decentering test didn't show any evident strong problem (perhaps just a bit, but it might be micro-motion blur). I wouldn't have bet on that for a used lens (I suppose most returned copies are due to decentering). The lens is pretty nice, so I really hope I won't find any problem in the next days. There are a couple of quirks that I have to investigate.