Quote Originally Posted by neuroanatomist View Post
He fills the frame with the test chart. The sensors are the same size, but the resolution is different. That's why the 5DIII at 22 MP appears slightly larger than the 5DII at 21 MP, and why the 1D X at 18 MP appears smaller than both. You see the same thing if you compare any pair of cameras with the same sensor format but different MP counts.
Yep, neuro nailed it.