I have the AFDII body & the AFDIII doesn't interest me because it does not have a separate focus control. I have posted about this before & I have never had any problems with the AFDII. I have heard that the 645 DF has a separate focus control? What I mean is that you can program the shutter release to just be the shutter release. My Canon cameras have been set like this for years as did my ZD camera. Loosing the film back makes sense. I sold my 645 AFD body for $400.00 USD on eBay last year & there are plenty of those 645 AFD kits on eBay. So if this camera has faster AF , separate focus control, vertical grip, leaf shutter lenses I would be interested. The difference between 1/500 & 1/800 is a half stop. Going from 1/125 to 1/500 is 2 stops well enough for flash fill outdoors. The Canon @ 1/250X works great anyhow. Ever since Phase started working with Mamiya things have been improving. Before 2006 not much was happening with Mamiya except for the ZD camera which took 15 months to come to market. Now that Phase is in control I think this will speed things up. I have owned the Mamiya AFD system since 2000. Before that a 500cm & to be honest I had more problems with the 500CM. Our choice is getting smaller with only 3 systems ( being made ):H3D ( closed ), Mamiya ( open ) & Hy6 ( closed Sinar/Leaf ). Of those 3 only the H3D & Mamiya have a 28 mm. And only Mamiya can take a Sinar, Leaf, Phase, & Imacon back. I also remember that when the Phase body ( AFDIII ) was announced that there would be a another new body coming next year ( 2009).
Denis