verdict, it's good you solved it yourself. I had the same experience with 2 D90 bodies, which had backfocus on fast lenses. Interested in how many bodies has this problem. When I used a kit 18-105 vr Nikkor lens i couldn't notice any backfocus probles, 'cos of small maximum apperture (3,5), so i found out backfocus problems when swithed to 50mm 1.4D Nikkor. I had terrible feelings about my new lens, because when i used it wide opened i had all shots out of focus... After some days of googling i solved the problem the same way you discribed above, but i'm still curious if Nikon tunes DX bodies focus for DX lenses or I just couldn't see backfocus problems in apperture set to 3,5 and smaller? May be the problem is obvious only on fast lenses?