EOS R will not fire using T-Ring - what am I missing?

[DHASr]

EOS R --> RF/EF Simple adapter  --> T ring (EF Mount)  --> 500mm F:8 Cat lens.  I cannot get the shutter to fire.  What am I missing?

I have been through the menu tree twice and have not seen anything that should be somewhere else, so what am I doing wrong?  I have used the T-ring and lens on my T6i with success, but not the EOS R

I have this lens, and three telescopes I would like to use in front of this camera.

[Waddizzle]

Okay, you say that you have been through the "menu tree" and could not find anything.  Have you read the full User Manual?

There is a default setting that prevents the camera from releasing the shutter when the camera does not see an attached lens.

[kvbarkley]

And you might have to be in P or M mode to see the "advanced" options.

[DHASr]

Thank You - I found it. That setting was down in the corned of the box under all the bubble wrap, but once I knew it existed, we found it.

I am a happy Canoner