I have been asked to post my tests comparing the RF 200-800mm vs RF 100-500mm. Unfortunately, I had only a few minutes with it at the local dealers and couldn't put it through my usual extensive tests but I do have some useful results on the relative resolution on the R5 and R7 vs the RF 100-500mm and RF 800mm. I have been taking photos of the rigging of a flagpole about 100m from the dealer for the past 10 years for quick testing. It has sufficient variation in the details of ropes, metal cables and stitching to see how well lenses and sensors resolve. The weather was unfortunately overcast on the testing day. Here is the flagpole taken at 500mm on the R5.