I understand that the problem only occurs with your Z8/Z9 and zoom F lenses (not f/5.6 F-mount primes), right?
And your friend’s 70-200mm f/2.8 FL ED works properly when mounted on the D850.
I know my answer won't help you, but my 70-200/4G VR works perfectly with Z6 & Z5II using FTZ or FTZ II.
Let me remind that Nikon Z cameras intentionally stop down the lens aperture during live view and autofocus only up to f/5.6. If you set your aperture to a narrower value like f/8, or f/11, the camera holds the physical iris at f/5.6 for composition and focusing, then snaps it to your exact setting the moment the shutter opens. This also applies to F-mount lenses.
Aug 14, 2026 at 08:23 AM
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