As I mentioned in my Zeiss ZF Lenses review, my D3x has been replaced by Nikon. I now have a brand-new D3x whose sensor-to-lens mount alignment has also been verified (by Nikon).
Brand-new and out of the box, the D3x actually had a hot pixel at ISO 100 in every frame, so it had to go to Nikon service to have the bad pixel mapped out (this is done routinely with all DSLRs, it’s just supposed to happen at the factory). I’ve got my fingers crossed that there’s nothing more than that to it. Nikon service was very fast and responsive, so kudos to Nikon there.
I’ll be checking two Zeiss ZF 21/2.8 Distagon samples to finish up my review. One is a replacement copy, and one is the repaired one back from Zeiss, the one that I bashed on a rock back on May.
To understand just how critical sensor and lens mount alignment are, read Ultra wide angle lenses and sensor/lens-mount alignment. And subscribe to Zeiss ZF Lenses if you really want the scoop, with examples.