| In all honesty, the pictures make comparison of the signal-noise-ration impossible. Mainly since the K20D shots are overexposed compared to the other shots. Or the others underexposed compared to the K20D. I'm not judging correctness of exposure. Since noise comes from pushing the shadows, relative overexposure helps reduce noise.
Quality of noise and relative increase in noise between stops can be judged better here. That looks great to me.
Wim |