Bellows restricting movements on Chamonix

Get the bellows out of the way like grat suggests and then you'll be able to use the full image circle of the lenses you have. If the corners go dark with no physical obstructions blocking light from the lens to the film, then that's what you get.

Keep in mind that front tilts and swings use up the coverage a lot faster than rear tilts and swings. Also make sure your lens is centered on the film for greatest coverage (unless you are purposely using rise/fall or shift). If your lensboard has an off-center hole, then you may need to use a bit of rise to get things centered.

Best,,

Doremus

The bellows is obviously damaged. Try re-folding it and see if it stays. It may or may not be salvageable.

Looks like you could simply reach in and push that sagging part of the bellows out of the way. Or try inverting the bellows (if that's possible with your camera).