An interesting camera allowing stereo work without the cost of a two-lens camera. Articles at the time explained how this could be achieved with an ordinary camera by shifting it between exposures when attached to a rail of some kind and using masks in the dark-slide.

The patent describes a stereo front to a conventional field camera allowing two exposures to be made on a single plate. The front standard is held between guide rails running across the front of the camera, it can be shifted along the rails and clamped in two positions for stereo work. A separate index line is marked to position the front for single exposures. To fold the camera the front standard is slid completely from the retaining rails after depressing a catch. The dark-slides are no longer present, they would have had some arrangement for exposing half of the plate at a time.

The patent is in the name of Len Holmes, L. E. Holmes and H. Holmes.

Houghtons also sold the camera as the Holborn Combination.