Giovanni Cappai

Confusing answer Joseph. I think the screens displayed in your picture are for the M645, the OP has a later Pro model (he also mentions the FE401 prism). What confuses me most is what you say about using the widest aperture to focus correctly when all these cameras work with the lens wide open. Only when manual focus lenses are used with AF bodies you need to do that or someone wants to check the depth of field in older bodies.

Mamiya 645 DF+, Phase One P65+

From memory, the issue was due to the film resting in the rollers and developing a bent. Solved by introducing a new back that came with the III giving the choice of having 15 instead of 16 frames per 120 film. It is very easy to see the problem by removing the dark slide having the back sit for a few hours and after advancing to the next frame. I did the test back then and verified. Never saw an issue on my pics though.

Mamiya 645 DF+, Phase One P65+:

Mamiya 645 DF+, Phase One P65+:

Fuji GX617, 180mm/90mm, Kodak Portra, Gold

Mamiya 645 DF+, Phase One P65+. various lenses (click on pic to see details in Flickr).

Thanks K.! It was not cropped, the panoramic adapter was in use with 135 film. This is one with Gold 200 in 120: Fuji GX617, 180mm

Mamiya 7II, Kodak Gold 200

Yes M., for the first a polarizer was used. If you click on the pics you can see more details in Flickr. No need to have an account.

Mamiya 645 DF+, Phase One P65+.

I have used both. Here are some thoughts on the subject: GX617 lenses are a lot sharper, at least in my case. GX617 viewfinders are actual finders not like the window in G617. Having said that both are almost equally inaccurate. It takes practice to visualize what the actual picture will be. Probably slightly better on the GX. G617 level visible from the view finder works very well both when shooting handheld and on the tripod. I have added a level on the bracket above the lens on both GX lenses for the same reason. The level on the GX617 is only useful when you want to place the camera absolutely leveled both horizontally and vertically. Film door seems a bit better on the GX but not so when on tripod (which in my case spends most of the time) as it interferes with head controls. Different design head may fit better. GX requires batteries only when you need to use the button on top of the camera. On the G617 is mechanical but on the stiff side. I usually use a cable release on the lens on both cameras. I don't know who the genius was, but the GX has no accessory shoe. The G617 has two. Both film door opening, and film release switches are much better designed in the GX. Having said all that, in my opinion there are two reasons to switch to GX: sharper interchangeable lenses. Everything else are just nuances.

No K. it's Portra 160.

Fuji GX617, 90mm & 180mm, Kodak Portra:

Mamiya 645 DF+, Phase One P65+, various lenses: