Thank you for all advice. Akira's point is what I was wondering about if Nikon does camera to lens calibration together. My most used lens on the DF are probably 24-140 f4, 50 1.8 G and 85 1.8 G, so I might send the zoom in too.
Rob.
Rob, I haven't have my bodies to calibrate with a zoom. If I were you, I might send 85/1.8G with the body, because 85/1.8G appears to be the most critical about the focusing accuracy among the lenses you named.