The camera obscura in Tarsem Singh's The Fall is an accidental one. In an early establishing scene the character Alexandria notices the shadows on the wall are moving…
It turns out the sun is low in the sky behind a horse in the courtyard and the shadows cast are being focussed through the keyhole.
Beyond being a lovely little scene it raises an interesting question. Is this techincally a camera obscura or is it a magic lantern effect? We're of the opinion that the image in a camera obscura is made up of reflected light while the image in this scene is formed by blocking the light and casting a shadow. Are we wrong?
It doesn't really matter though. The film is a criminally underlooked gem (comparisons might be The Princess Bride and Life of Pi) that you should definitely seek out. Here's the 20 second scene in full.
Thanks to Chris Plant for the tip