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@YuengLinger had some issues with critical focus on a couple of copies of his 100-500 which he sent back and now has a good copy but I do not think he had results as bad as the shot you have posted...
Friendly correction, I've only had AF issues with one copy. My first copy was excellent, but when I called Canon Pro Services early on, before they had been informed about image stabilization design changes, they thought my copy was not working properly because the IS element didn't park. They recommended that I return the lens while in my return window. Of course this turned out to be a mistake: The Rf 100-500mm is designed intentionally to not need parking. An excellent tear down by lensrentals.com, and lots of discussion online, led me to understand the new design sufficiently to be confident the lens is rugged enough for hiking, etc.
However, I did order a new one that was obviously subpar, though at first I didn't want to believe it, and I got a bit discouraged. But who knows what forces gear is exposed to during shipping? Or whether we might be receiving somebody's return? In any event, I missed the lens's compactness, weight, and performance so much that I gave it one more shot, and now I have another excellent copy. AF, IS, and IQ, all absolutely top notch and consistent.
It has taken me a long time to learn to reduce the emotional intensity of buying an expensive piece of gear--or to at least live with the suspense and anxiety. Just my personality, I guess. But when I see generally trustworthy reviews and sample images from smart photographers, and I read opinions here on CR expressed by members I've come to trust over the years, then find something I've purchased not behaving as expected, I know that it is easier to exchange an item than to agonize over it. Plus, I have become, over the years, more confident as a photographer, so I can troubleshoot methodically to eliminate user-error.
I knew very quickly, for example, that my second copy had problems, because I had already taken photos with an excellent copy, and because I was seeing proper results posted online--while reading praises from some very demanding photographers here! Despite all this, I still was ready to give up on the lens, to mumble "sour grapes." I'm glad I didn't.
The Rf 100-500mm might be a little slow at f/7.1, but with the new sensors' high ISO performance, and the compact design of the lens, it is the right longer-focal-length option for me. The lens is easy to use on walks, even if I'm with my two little kids. I can't imagine having the time or patience to drive to a special location with a Great White, tripod, and gimbal, and then sit with the mosquitoes until a bird does something interesting.
But I raise a glass to the intrepid nature photographers who are willing, and who bring back so many great moments!
Another note here: Despite being "experienced," I hadn't shot at over 200mm for at least two years before getting this lens. Getting sharp shots handheld at 500mm
consistently, even with remarkable IS + IBIS, doesn't just happen. It is taking me trial and error, and plenty of practice. Making sure my shutter speed is high enough for creatures flying or swimming or even walking is a challenge. Light as the lens is, after holding it to my eye at the ready for more than a few minutes, my hands begin trembling more--and I can see it when reviewing my images, how a static subject starts jumping around all over the place in the frame. And even at f/7.1-f.10, depth of field can be an issue. At f/11, I think I'm seeing some tiny bit of softening from diffraction already. So this is a lens that needs patience, practice, and understanding of its limitations. Sometimes I need the tripod!