An almost non-tapering calico double-extension bellows is employed; allowing the projected image to freely reach the photographic plate regardless of lens offset position.

For insertion of the wooden dark slide plate cassette, the hinged focusing screen is swung up and away.

However, some were made available with a spectacular focal-plane shutter, recognisable by the brass mechanisms either side of the back panel.

The bellows extension would allow a selection of focal length lenses to be employed covering the required field of view.

The back panel may be tilted and turned slightly, and at the front, the lens plate may slide vertically and horizontally to control perspective and distortion.

[1] A black cloth is required to keep stray light out while observing the image on the ground glass focusing screen.