Turn on the Electronic Shutter option and put the camera in Mirror lock-up mode. You will have zero movement inside the camera at time of shutter release if you are using a cable release. Alternately you can also enable shutter delay (I recommend 3 seconds). Now if you push the shutter button twice, the mirror will be up, the electronic shutter engaged and 3 seconds later the photo is taken, again with zero internal movement in the camera. The difference at some shutter speeds to what was achievable on the D800E or the D810 using the normal focal plane shutter at time of exposure can be significant in fine detail.
Of course none of that is that useful if you are shooting handheld as per the title of the thread.