Panasonic GH2 vs Pentax K20d vs. Pentax K-x

GH2 with 20 F1.7 @ ISO800, F1.7, 1/60
K20d with DA40 F2.8 Limited @ ISO800, F2.8, 1/20
K-x with DA35 F2.8 Macro Limited @ ISO800, F2.8, 1/25

A new M43 vs an old APS-C vs an entry-level APS-C. Can you tell which is which?