I have a 5DS R rental from lensrentals for the weekend. Yesterday I took it out to the Oneonta Gorge and for a couple of the shots I had it set to -2 2/3 exposure compensation by accident. I decided to see if those images could be saved in post. I've owned the 7D, 5D Mk II, 5D Mk III, and 6D. I can say that this new sensor from Canon is easily the best one they've ever made in terms of shadow noise. It never would have worked with one of those older bodies. The resulting image had a reasonable amount of noise and loss of fine details, but I would consider the image salvaged.