There are some camera features that have no use for me, and perhaps that is true of illuminated buttons for some users.
But for my shooting at the edge of light into late dusk, non-illuminated buttons have forced me to use my iPhone as a flashlight or some other smaller flashlight at times. This is actually quite troublesome, because I don’t really want to carry an extra (red) LED flashlight—regular LEDs tend to wreck night vision, and I’m no spring chicken any more and don’t have great night vision in my 6th decade of life. Well, the rear LCD is another problem including the fact that it does not count down in seconds for long exposure noise reduction (I hope that’s fixed).
So the new illuminated buttons in the Nikon D850 are a nice problem solver for me. No flashlight to carry and I can be sure of seeing the buttons when I need them.
Ergonomic operation offers confidence even in the dark — Button illumination and layout
The superb performance of the D850, such as its low noise at high ISO settings and wide detection range for AE, encourages time-lapse photographers to venture out in the dark and create amazing images from challenging situations.
The camera offers illuminated buttons on the rear left side and release mode dial, making it easier to change settings when shooting in the dark.
Moreover, the buttons and dials are arranged in a convenient ergonomic layout to fit photographers’ hands. The rear side now features a sub selector added in the same position as for the D5, to allow easier right-handed operation by photographers who use both models.