1924: Contessa-Nettel Ergo
Due to the way several camera manufacturers amalgamated, this model was was made by three different companies. It began with a small German camera company called Contessa. In 1919 that company joined forces with another small camera company called Nettel to become Contessa-Nettel. Then, in 1926 Contessa-Nettel became one of four camera companies that merged to form Zeiss Ikon. The Ergo was first made by Contessa in 1912 when it was called the Argus. It continued to be made under that name by Contessa-Nettel when the two companies merged. Sometime in the 1920s, probably around 1924, Contessa-Nettel renamed it the Ergo. From 1927, under its new name, it was made by Zeiss Ikon.
It’s a detective camera, but don’t confuse that with a spy camera. Detective cameras were made for photographers who had nothing to do with espionage, but who were fascinated with equipment that could be used unobtrusively. For that purpose, the Ergo shoots pictures at right angles to the way the photographer is facing.
It looks like a small monocular but what appears to be the lens at the front end is false, even though it is surrounded by aperture settings marked f/4.5-36. The eyepiece at the other end, which appears to be looking through the fake lens, actually uses a mirror
to look sideways at the subject through a smaller hidden opening. As the shutter button is pressed, a flap in the side of the body, at right angles to the fake lens, opens to reveal the real lens. The shutter fires and the flap clicks shut. Focusing and shutter speeds are adjusted by tiny knobs on the side of the body and it shoots pictures on 4.5x6cm plates or sheet film in film packs.
The Contessa-Nettel version of the Ergo detective camera.
Above: What appears to be the side of the camera is actually the back, holding a ground-glass focusing screen under a hood, interchangeable with a film or plate holder.
Below: How the lens flap opens and closes as the shutter release is pressed and the picture is taken.