9021501 -- seems to be good at first sight, a bit soft wide open at 16mm in the corners. Bought at fotokonijnenberg, turnhout, belgium.
Seems like the newer 902... serials are all good up to now.
update
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I uploaded some testshots. Could someone with a good copy take a look and tell me if I got a good one?
Picasa Web Albums - Beau - DA* 16-50 f2....