I use a Canon R5 along with the RF 100-500 lens, how do you guys using both last feel about the noise levels generated by this combination?
I shoot a lot of birds in flight and all in the uk where our light isn’t the best!
That combination should be about as good as you can get. I follow another Bird Photo blog by a photographer with several decades of bird photo experience (mostly Canon but more recently Sony) , and he has nothing bad to say about R5/100-500/with or without 1.4TC. If you're worried about noise, noise reduction software like Topaz works near miracles at ISOs of 6400 and up.