EOS R adapter question

[Wandalynn]

Just curious...Does anyone know why Canon recommends connecting the EF to RF adapter first to the lens before attaching it to the camera? It would be so much easier to just leave the adapter on the camera but I'm following the recommended procedure.

[RobertTheFat]

Possibly the adapter has to establish communication with the camera before it can assist the camera in establishing communication with the lens.

[diverhank]

I agree with Bob.  If you don't turn off the camera when mounting, errors might occur if you mount the converter first then the lens.  I had a lot of problems with mounting teleconverters then lens on 5DIII before (Not all the time but the camera would sometimes freeze.  Had to remove the battery before the thing would revive).  So I've learned to mount the converter or adaptor to the lens first then to the camera.

[jrhoffman75]

Canon doesn’t explain why, but does state to do that.