What is the best way to take crisp, sharp pictures of the eyes with the Nikon D850? Does it have an eye tracking system? - Quora
Eye or face detection?: Nikon FX SLR (DF, D1-D5, D600-D850) Talk Forum: Digital Photography Review
Nikon D850 Review & Sample Images by Ken Rockwell
Amazon.com : Nikon D850 FX-format Digital SLR Camera Body w/ Nikon AF-S FX NIKKOR 24-70mm f/2.8E ED Vibration Reduction Zoom Lens with Auto Focus : Electronics