Disclaimer: This is Not a scientific test. I set out to create a useful comparison to help me understand the differences between the images from these 2 very different cameras. Let me know if you have any questions.
When I first pulled these shots in Premiere Pro and started to line them up side by side I was instantly amazed at the difference in detail from the Canon c100 over the 5D Mark 3. Now, don't get me wrong, I love the Canon 5D Mark 3. We've used them almost exclusively since they were released in 2012. However, it is hard to argue with a side by side comparison.
I found myself asking if I had just missed focus on the 5D Mark 3 since the images looks so muddy and blurry next the Canon C100. I know I had it in focus as I was taking my time as much as possible. A lot has been said about the soft images coming out of the 5D Mark 3. I've known this was an issue since it's release, but without a true "apples to apples" comparison it's more difficult to know for sure what you are getting.
The increase in dynamic range from the Canon C100 over the 5D was really noticeable on the last shot (sunset) as you could see into the shadows more while still retaining a ton more highlight detail. The sky rolled from darker blue to the bright area of the sun, while the 5D went to just blown out white quickly.
Overall, we are loving the increase in image quality, ease of use, and seamless integration into our workflow we are getting from the Canon C100.
Let me know if you have any questions!