I am using an AF-S 500 F4 G solo and with TC on a Z8.
It works great and - to be honest - it works even better than with my D850 before.
It workls so well that I wil try to do something which in DSLR times was regarded as no-go:
Combining the f4 lens with a TC-17E II, giving me a 850mm f6.7 combo that is on par or even better in resolution than the Z 180-600 solo at 600mm and for sure far better than this lens combined with a TC-1,4x giving you 840mm with f9 to start with.
It 's certainly worth the experiment, because it costs virtually nothing compared with a similar quality Z system alternative.
Yes, it's a heavy combo, but this is something I only need for stationary work with tripod anyway. For the agile and flexible walkaround work the Z 180-600 is perfect.
Especially the F-mount 500 f4 (G and E) were so sharp that getting a good one used should be a temptimg alternative for any Z user needing long lenses and if I didn't have the G already I would go for the E, because is significantly lighter and much less front heavy due to the FL elements.
And another example from another world could have been the Micro AF 200mm f4 D, which is a top notch macro lens of a kind that simply doesn't eyxist on the market these days. The bad news is however: I can't get mine working on a Z8 - no way ! So, it has to go and find a new home, where it can live together with a D850 again ...
IMO the only downsides could be:
- Potential risks of additional connections because of the FTZ needed
- Lack of configurable user elements, especially the ring(s)
- Potential risk in terms of compatibility / flexibility with configurable user elements on F-mount lenses (i.e. buttons)
E.g. with my AF-S 500 f4 G assigning the buttons on the lens to functions procvided by the Z8 doesn't work correctly or not at all
But in the end, my dreams are not far apart from those of many others: Z 400 f2.8 TC with an additional TC-2.0x and off you go