Just a small sample I did today. Both cameras focused a bit different (my fault) bit nevertheless it shows the difference. give or take 1/3rd of a stop.
I suppose I don't have to say which one is the 620 and which one the k-5 ;-). The E-5 would have about the same shadow recovery but having a tad more detail allows it to filter the noise out a bit better.
This is ISO 100 for both, +4 EV on the LightZone raw slider (its max).