Having nothing to do (Corona and cold weather, light snow) I did some research and further tests.
One thing that is important, mounting a non-CPU lens on the Z-kameras with IBIS, is to set the proper values in Settings Menu (Tool -> Data for Non-CPU lens) so IBIS get the right information about what lens that is mounted. You can specify up to 20 lenses, it's not only focal length but also the biggest aperture.
When switching non-CPU lens, this has to be changed as well. Only one focal length can be set at a time, how to deal with older zoom lenses, I don't know.

I have one 200mm, when Non-CPU setting is on 50mm the picture is rather shaky, when on 200mm it's much better.
I also have an old 50mm lens, when Non-CPU setting is on 200mm, the picture is very shaky, when on 50mm it's much better.
So this setting is important when it comes to IBIS performance.
All new lenses (Z-lenses) do this automatically. I guess that all F-lenses with an CPU manages this automatically.

I found some descriptions about VR and IBIS, where more info can me obtained
https://photographylife.com/lens-sta...-stabilization


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