I have a dust bunny in my 5DSR and air will not clean it. This is a problem for videos. I did some test shots at f4.5, f9 and f22. They all show the spot to some degree when viewed on a grey surface, like fog. I found that I can open a set of files in ACR and select all of them. Then I can use the spot removal tool to fix it. It fixes all of them in the group.