Cannot shoot my R5 with a Samyang 12mm lens and a canon RF adapter, why?

puffo25

EOS R5 - Fine art landscape, travel,astro and pano
Jul 18, 2017
76
20
55
italy
Hi, I got finally my new Canon R5. I can shoot with my EF lenses using the RF adapter. And I can of course shoot with RF lenses too. However with the manual focus Samyang 12mm fisheye (canon mount), when I am in manual mode, using the RF mount, the camera will not fire-up. Any clue?
 

Mt Spokane Photography

I post too Much on Here!!
CR Pro
Mar 25, 2011
16,528
1,484
If the camera will not start up, there is likely a short in the lens connection somewhere. If it starts up you can't take a photo, set to release the shutter without lens as noted above. All Canon DSLR's have that setting, you set it once and forget its there years later when you replace the camera.