Mount Adapter EF-EOS R question about compatibility with Extender EF 1.4x III

[A_Random_Dude]

Hi, all:

I'm considering adding an R6 Mk II to my camera bag in the new year, which would be my first mirrorless. I know that I could use most of my Canon EF/EF-S lenses using the EF-RF adapter.

My question: Does anyone know if it's possible to use the 1.4x III extender in combination with the EF-RF adapter? As in this scenario: 100-400mm II > 1.4x extender > EF-RF adapter > R6.2.

Just curious; thanks in advance for your input.

[kvbarkley]

Ken Rockwell shows an EF 100-400mm a 1.4x teleconvertor *and* a 2.0x teleconvertor on an R:

https://kenrockwell.com/canon/eos-r/r.htm#perf

It is goofy, but it worked.

[A_Random_Dude]

Great to know. Thanks for that!

[Peter]

I tried R6+adapter+x1.4+x2+EF800. AF still works but the lens correction will not when only one teleconverter is reported in Exif.