I tried one on my D850 before the D850 went back, its a decent lens but if I'm honest I didn't really think it was all that much better than the older 24-70 USD lens and certainly not an extra £700 odd... AF speed did seem a little snappier but IQ seemed very similar to the older lens, I have read that the new one is better at longer lengths (longer than 50mm) than the old one though but that wasn't something I really had chance to try out.