Sorry for the seemingly stupid question but I'm used to using Fuji with a mechanical dial that works. I have only just picked the D750 up but I am finding the only way I can manually control the aperture on this DSLR is by physically setting the mechanical aperture ring on the lens to F22 and then rotating the front sub command wheel on the camera. I'm assuming this is normal for this camera given there is only a tiny amount of space to physically rotate the mechanical aperture dial with your finger on these lenses and that when doing so it does nothing but give an FEE error on the display. The lenses I have tried are the 24-85mm 2.8-4 D, the 50mm Nikkor 1.8 & the 50-200 f2.8 D. Edit: Ignore. 20 mins of ruling out dirty contacts and not having the lense seated correctly on google states I am correct.