Just wanted to update status of my 600mm D issue with the z9. Well its really was the FTZ and its design. Seems the D series have an outer tab that is associated with the aperture ring on the lens. The FTZ is designed so this tab with activate a switch on the adaptor but it can mis-align and in my case be missing altogether. See the attached photo and also ones in this link
https://www.dpreview.com/forums/thr...-1jb0dSbgGaQANuICxMOggtJ0yVqHL8LXSh97zYy_BjJE
The funny thing is my D850 has no such tab to activate this switch and the 600mm lens works just fine, so there is some electrical interface that the 850 uses that has to substitute for this mechanical one. You think Nikon would try to use both methods to be redundant. (any one have any connection at Nikon?) But that also means today's engineers would have to think about double redundancy. Furthermore, even with the aperture error message... the AF still works. I hit AF ON and the lens will autofocus even though I can't see the center portion of the screen, you can see the outside edges in good focus. The camera just prevents the shutter from triggering.
Bottom line my 600d does not have any tab that activates this switch and so I get an error and locked out from firing the shutter. I can manually insert a small piece of plastic to activate the switch and all is then working. Nikon no longer supports the 600mm D and so I either have to DYI or find somewhere that may have cannibalized another lens.
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