Canon's Lens Adapter- Filter Holder - Simple yet Invaluable

[chambeshi]

https://www.dpreview.com/news/0628186309/three-ef-to-rf-adapters-available-for-eos-r

perhaps Nikon will wise up to its potential - http://www.naturalart.ca/voice/blog.html

[Ilkka Nissilä]

There may be some unwanted optical effect from the addition of the filter in a position of the light path where it was not intended when designing the lens.

[Erik Lund]

Well if you design the adapter with a neutral filter always installed it's ok i guess for long lenses, just like the longer Nikkors has drop in filter inserted as standard. It's just very different how WA lenses react to glass thickness at that point,,,

[Birna Rørslett]

In a not-too-distant future , where Z cameras are modified to be "full spectrum" or similar, having a rear filtration option for various exotic lenses should offer a great advantage. This approach works well on my modified Panasonics, so no reason it wouldn't apply to the Z range as well.

[MILLIREHM]

I hope the Z-cameras will be good full-spectrum cameras as well.

[Birna Rørslett]

My prime target for conversion at present is the Z6, but unfortunately I might not have my own camera in hand before November. Whether a conversion is feasible remains unclear -- time will show. The Z7, arriving hopefully in a couple of weeks, will not be modified though as it slots in besides my D810 for macro work.

[MILLIREHM]

https://www.dpreview.com/news/0628186309/three-ef-to-rf-adapters-available-for-eos-r

perhaps Nikon will wise up to its potential - http://www.naturalart.ca/voice/blog.html

Read the links now, fine blog, thanks (also what he writes about the D5 being superior to Z or A9 regarding the wildlife camera)
I'd also like to buy several adapters for different purposes if available
The 12-24 mm F/2,8 could also be fine if that solution works - but thats Ultra wide and maybe more delicate