Hi,
Did you test the Mamiya 300 F4.5? the white body lens? On the GFX how did you control aperture, I would love to use this lens but the Fotodiox adapter will not work the aperture of the more modern Mamiya glass.
The older 300 F2.8 APO, will work, but is massive and hard to find now. The 200 F 2.8 is also excellent but also getting hard to find a good copy.
Would love to see a Schneider/P1 adapter some day for the GFX that would allow some excellent optics for the GFX as an alternative.
Thanks
Paul Caldwell