At the risk of being considered rude, my comment is one of suspicion. The author said that he put the two lenses on two different 5D3s and took casual snapshots around his home. So how is it that in each pair of shots, the composition and focus are so identical? And how the heck did he get the dog to stay absolutely perfectly still while he switched cameras?
Check the EXIF, it is from two 5D MkIII's.
I was actually putting a comparison selection together, with adjusted colours and contrast, even at 100% the images are identical, but the focus points are very different in each pair so it falls down a bit.
To be sure, anybody can make the colour and contrast of these two lenses identical, even with just jpegs. The most strikingly different pair, the stereo/cable box (?) lights are focused on completely different planes so the blur comparison is fatally flawed there too.