None, but I haven't really went hunting yet. The birds above just happened to be there when I was on vacation. So I have only a hand full of pictures with birds to far away so far.
It has been very noticeable only twice otherwise in 4000 pictures. One building skyscraper with highly defined vertical lines and the Waldo picture I posted in another thread.
This weekend I am taking it out with the 500mm. All my feeders are empty so my results may be limited to hunting only. I have high hopes for the 5Ds R and wildlife.