Not quite a head to head of the same footage but a good chance to compare video from a Canon 1D Mark IV, 5D Mark III, and C300; all shot with a similar lighting setup. The 5D Mark III footage did have sharpening added in post (2.5 in FCP X’s Sharpening Filter.) The other samples did not.
Differences are visible but are a bit toned down because of Vimeo’s compression. To watch the videos at their best run them full-screen with the scaling turned off. To get the best sense of sharpness and tonal range take a look at the attached frames. I recommend right clicking them, selecting “open link in new window,” to see the frames at *full size (1920 x 1080.)
*In Safari you may need to click the enlarge icon for a 100% view.
Canon Cinema EOS C300
Canon 5D Mark III
Canon 1D Mark IV