Canon RF 100-500mm - use an adapter or not?

B&H Photo shows the Canon RF 100-500mm lens on their site (not available, just listed).

In the Q&A section, someone asks if the lens can be used on the 7DII. A staff member left an interesting answer.
He said no, the lens cannot be used on any Canon dslr, only RF cameras. No mention of a EF-RF adapter.

So did the staff member get it wrong, or maybe he knows something I don't.

https://www.bhphotovid​eo.com …00_500mm_f_4_6_​3l_is.html

Also, anyone want to guess at the price?

It's an RF lens. Like all RF lenses it is for RF bodies and will not fit or work on EF bodies.
Register distance is the distance from mount to sensor. RF is 20mm. EF is 44mm.
That is why there is no adapter to fit RF lenses on EF bodies and why there is an adapter to fit EF lenses on RF bodies.
EF to RF adapter is 24mm length. An RF to EF adapter would need to be -24mm which is obviously not possible.

I don't know if it would be possible using glass inside the adapter to make an RF to EF adapter possible but I suspect if it was possible, the performance would be poor. Then you would have the problem of the extra electrical contacts on an RF lens. RF body needs to communicate with less contacts on an EF lens so that is possible.
Could an EF body control an RF lens? Probably not. Moot point, due to the massive difference in register distance.

RF 70-200 is $3999 so I suspect RF 100-500 will be $3399.

Thanks for clearing up my confusion.
Now I understand.

Well, looking forward to seeing how this lens and the R5 will work together. An expensive combo for sure, but might work great for air show photography.

Skill is by far the biggest factor for Airshows.

https://photography-on-the.net …/showthread.php​?t=1498567