Here are two scenes taken with the Canon 5DS R, Canon 5D Mark III, and Canon 5D Mark II during the day at the lower ISO ranges. The first scene is from ISO 50-400 and the second scene is from ISO 50-1600. The second scene is good for showing how much you can recover shadow detail.
Here’s how I performed these tests. I setup my tripod (Slik 700DX Tripod and Bogen 3030 3-way pan/tilt head) and mounted the Canon EF 70-200mm f/2.8L IS II USM Telephoto Zoom Lens to it. I attached a camera body to the lens, turned off IS and turned on AF. I turned on live-view, zoomed in, and focused the lens. After the lens was in focus I turned off AF. Metering was determined by the first camera body that was attached to the lens and the same settings were used for the other two cameras. I then proceeded to take the shots in live-view and changed the ISO and shutter speed between shots to keep the exposure consistent. Once I was done with one body I would switch bodies and repeat this procedure. For the white balance the camera was set to cloudy since it was very cloudy today.
All JPEG files were converted using Canon DPP v 220.127.116.11 with the sharpness and denoise settings the same as when the camera took the shot at that ISO.
The second scene is good if you want to try lifting the shadows and see how much extra detail you can show: