Blade Canyon
Senior Member

Okay, here is a 100% crop from your RAW file (from a D610, not a D850 for those just joining us).
I enhanced the saturation and there is some noise in the unfocused parts of the photos, but it seems very acceptable at this magnification. I don't think there is anything wrong with your camera. I had two D600 bodies and loved them. I upgraded for no good reason, just to get the latest greatest 46 mp.
ETA: I did not add any noise reduction.