User ID wrote:
The difference is clearly the user.
To doubt the above diagnosis would just constitute a most emphatic confirmation of its accuracy.
You can very simply test this for yourself. Use a tripod, focus using magnified live view, and shoot at f:8. The D750 has a low pass filter, so you should normally apply just a small degree of sharpening either to your camera settings or in post.
It is always THE PHOTOGRAPHER! Technique is the determining factor in ANY photograph. Equipment helps but is not magic.