I cannot say what is causing this but its way beyond softness. When I test for focus I always try to find the focus line. This is usually easy to find and then its usually easy to make a focus correction. With the GFX 100 I can find the focus line but it is also not in critical focus. There are also some other issues that are very disturbing. There is some kind of a flare occurring when shifting. Flare may not be the correct term, fog may be a better term, but a portion of the image in the upper center gets brighter when I shift left or right. This doesn't occur with every shifted image. The same type of shifting using my 3100 does not produce this anomaly. There may be something going on with the sensor glass. Regardless that in itself would be enough for me to not to want the camera as using it with my Tech camera was one of its major intended uses.
I'll more than likely just wait this one out as I have a 4150 on the way.
Victor
Sorry to hear that Victor. Can I share my experience with you about my experience with GFX and Actus. like you I have using this system for awhile, I have even modified the bellow to a custom made lamb skin below, very narrow and almost no distance to keep my flange as close as possible as GFX flange is bit on the long side. One thing let to another, one day, I discover a long stretch of fog/red patch on my images while using GFX to do some stitching works. I thought it was my lens that is the problem. But ended up, it's camera handle pushing the bellow too much until a small gaps has appear at the magnetic seam.... light leaks.... And then another time... the same problem occurred, and I have check the connection of the bellow, everything seems fine.... I thought, this must be the lens again! only later to find that, again, it's the bellow.... a screw has gone missing at the ring, and it make the bellow slight loose on the metal ring part....
All I want to say is, check your bellow, cause it might have been push out of alignment by the camera, particularly this GFX100 as the size is just way too over and generate light leaks...
By the way, Cambo is coming out with a new attachment and shim for GFX100 to work on Cambo Actus.... so you can do a normal landscape shoot, except that it add 12.5mm to the flange... ouch....