A while back I was getting more than acceptably sharp images with this combo tracking quickly moving subjects, auto ISO, 1/800 (plenty of light, f4 to. f8), hand held (sometimes on a monopod), back button auto focus, shooting CH (continuous high, up to 7 frames a second), VR Sport. Sharp, no more. I fine tuned the lens using a Michael Tapes target, adjusted to -17. Single shot, static subject- fine, tack sharp. Moving subject, lousy auto focus. Is this likely just a lens issue? or the lens and the D850 body? If I send the lens or the lens&body down to Nikon Service in SoCal will they give me a detailed report on what they find, or just an invoice?
