126 roll is roughly a roll-film equivalent of half-plate: the plates are 4¾x6½-inch.
Looking at the photo, I wonder if it might be an SLR, but turned on its side (suggesting it doesn't have a rotating back).
He seems to be holding a handle on the left of the picture, attached to what would normally be the top of the camera, which would be a folded-down reflex hood. To use the camera like that, he'd have to be using it as a view camera, with a rear ground glass. If my idea is right, the front of the camera isn't racked out at all.
The flap lens-cover on an SLR usually (but not always) opens upwards to form a simple shade, as we see it.
My idea runs into trouble then. Those knobs on the top (the top as we see it) have to be a knob for the rack-and-pinion (on our right) and a winder for a focal-plane shutter (on our left). But if we set the camera upright, they'd be on the left side of the camera, and the shutter winder is 'always' on the right (my Ensign Reflex has a focus knob on each side; don't know if all other cameras do). So I think my idea depends on the photograph having been reversed left-right.