Hi, ... (SONY a7ii -
ZEISS Sonnar 1,5/50 f 1,5 ) :
I told you above that years ago I bought SONYs to adapt Leica M mount lenses, with varying results. Some worked well, some less so.
Over the years, I bought many native SONY lenses. So, today the only M mount lenses I still attach to SONYs are the 12 and 15mm VOIGTLÄNDERs.
The performance problems of M-mount - SONY combos result from the thickness of the SONY sensor stack.
Now, there is the NIKON Zf, which looks nice, and has a sensor roughly half as thick as the SONY one. With native manual VOIGTLÄNDER z lenses one gets focus confirmation, because these lenses have contacts.
Normal M mount lenses (without contacts) only have the focus area magnification function in live view, which is also featured on the SONYs.
So, I attached my M mount ZEISS Sonnar to my SONY A7ii and went for a walk.
I could live with the focus area magnification function in live view.
But I do not feel the need to buy a NIKON Zf.
And there is always the temptation of native Z lenses, which might lead to the purchase of another camera system in the long run.