That argument sounds counter-intuitive, to me. I would think the thumbwheel stops of Leaf Verto would give you an instantaneous 'feel' for the orientation of the sensor without even looking at the camera.
David
What I'm saying is: I don't even want to pick up a camera, (any camera), that forces me to worry about what orientation the back is in. Period. End of story.
When I'm working spontaneously, what I see in that viewfinder is what I want to be captured by the sensor.
I don't want even one ounce of (dwindling) brainpower to be devoted to "which way is the back set to?"
Both the Leaf and the Sinar have a viewfinder with twelves "sides" to it. Not good. One opinion only. Would be fine for repetitious studio work though, I'm sure.
I react to what I see in the viewfinder. Pure and simple. Here is my inner dialogue when looking thru that Leaf/Sinar/Rollei/Whatever: "Ok, the back is set to Vertical, so that means that even though I'm seeing all that extra stuff there on the left and the right, that means it's not really being captured, but that stuff up at the top and at the bottom is being captured, so I'm going to compose the frame accordingly". I've got enough inner brain dialogue when I'm shooting. The viewfinder image should relax a person; not add confusion.
As awkward as it is to turn the camera body on its side, like the Contax or H1 or Canon, I'd rather do that, and always be seeing EXACTLY what I"m shooting, rather than that twelve sided Afi viewfinder image. The Sinar viewfinder simply needs blades. They should buy a Fuji 680 Mark III on ebay (for a hundred bucks), (the greatest camera ever made), and then copy that blade design. Now that I think about it, the blades in the 680 were in the Body; not in the Finder. The finder 90 was just a piece of plastic. But the film back orientation would "talk" to the blades, and they'd stayed in sync with each other.