I like the first one for the expression. Between the first two images, I'd guess the first is with the 50D and the second is with the 5DII. The framing is similar (although the angle is different), and the second one has shallower DoF and also shows a little bit of vignetting. I'll guess that the third image is from the 50D, because if you moved in that close with FF, I'd expect more OOF blur of the chair from the thinner DoF (unless you stopped down the aperture for the shot).