I would expect Nikon to make an adaptor fully compatible with only their latest SLR lenses, AF-E, and then tell users where earlier lenses weren't compatible/usable. With AF-E lenses, anyone with a camera older than the D5 can't use them so there is already some loss of backward compatibility in the lens range. Body incompatibility with earlier lenses has been a factor since the F5, the F4 being the last camera to have a folding AI coupling. I am of the opinion that Nikon has chosen not to enable metering with older lenses as a deliberate policy. Though their meter coupling has always seemed a bit Heath Robinson, I never felt that other manufacturers had such a rudimentary coupling.