Thanks to All,
actually I know that the 31 megapixels is 33x44mm and the 39megapixels is 36x49 (about), but as hcubell says I saw the 28mm Mamiya with thw P30 producing strange behaviour in the corners... Just to say, go to captureintegration.com and you'll see some test...
Overall, i think the difference I can see between my files and the David's files it's first of all in the different subject, and secondly due to the fact that I'm not used to the Hasselblad system, I'm pretty sure that I can do more after have studied and tested the enitre system. But I guess it's useful to see what Hasselblad can do in a beginners hand. I think Hasselblad has a great potential, but I wish I could use the H3DII with a PhaseOne back... Hassy is a very great platform but, and it's just a feeling a mood, I don't like very much their backs...