One of the things that I knew would be a limitation of the RF 200-800 was the aperture which is a lot smaller than for really expensive lenses (yes, it is also expensive but not in the tens of thousands type of expensive).  In low light, this is going to be an issue and it would be interesting to see how things worked out.  When I got home with it, I was sitting on the deck when some hummingbirds started feeding on the flowers in one of our beds.  This area is in shade a lot of the time so light was limited.  I was rather pleased with the effectiveness of the focus, the sharpness at full zoom and the relatively limited noise related issues from the R3.  This is a combination that looks like it could be quite useful for a wide variety of occasions.  Not the solution for everything but definitely versatile.