DPreview added the Fuji GFX studio samples. The camera uses the Sony 51MP medium format sensor. But despite the size advantage there doesn’t seem to be a big quantum leap over the Sony A7rII:
“In terms of high ISO noise, the GFX 50S performs fairly similarly to the Pentax 645Z and, as sensor size alone would lead you to expect: better than the Canon EOS 5D SR. However, because Sony’s a7R II sensor uses a more modern BSI design, it’s able to be more efficient, which means it’s able to close the gap to the bigger sensor cameras. “
As I stated many times I think Sony should use the much larger 55x41mm sensor if they ever are going to make a medium format RX or system camera. That should really give us a visible difference in both, quality and esthetic of the images.