09-15-2010, 05:09 PM
It's difficult to find RAW files of the same subject taken with the GH1 and the original 1Ds, but the JPEG's available in imaging-resource.com still give some picture as to how close these two are (the Panasonic is actually better in most of them, thanks to its better, more modern, JPEG engine):
http://www.imaging-resource.com/PRODS/EOS1DS/E1DSPICS.HTM
http://www.imaging-resource.com/PRODS/DMCGH1/DMCGH1IMAGING.HTM
As for the Mamiya, medium format cameras in general are not really intended for high-ISO photography, so it's not that surprising that the ZD provides better quality than the GH1 at low-ISO, and fall a bit behind at its highest ISO:
http://www.imaging-resource.com/PRODS/EOS1DS/E1DSPICS.HTM
http://www.imaging-resource.com/PRODS/DMCGH1/DMCGH1IMAGING.HTM
As for the Mamiya, medium format cameras in general are not really intended for high-ISO photography, so it's not that surprising that the ZD provides better quality than the GH1 at low-ISO, and fall a bit behind at its highest ISO: