The Aquamatic (and Aquamatic 1a and Aquamatic II) are underwater cameras for 28 mm-square images on 126 film cartridges, made by (or for) the French company Spirotechnique. The company had already made the 35 mm Calypso, which is substantially metal-bodied. The Aquamatics are made mostly from moulded plastics. The cameras were designed by Jean-Louis Défuans, and at least the Aquamatic II was later sold under his Formaplex brand. The camera was guaranteed for use at up to 75 m.
The first model of the camera has a 35 mm f/8 lens, which underwater is effectively a 26.5 mm (because the lens' first curved surface is in contact with the water; in contrast, the Calypso has a flat glass protecting the front of the lens, so gives the same angle of view in and out of the water). The Aquamatic has aperture stops (fixed stops in a sliding metal strip) f/8, f/11, f/16 and f/22. It has shutter speeds 1/50 and 1/100 second. A close-up lens is attached on a short leash. It can use Magicube flash-cubes. It has a simple frame-finder.
The Aquamatic 1a (pictured here) and II have improved specifications. The sliding, captive transparent strip on the front allows one of two different close-up lenses, or neither, to be positioned in front (i.e. the camera now has three-zone focusing, at 2.5, 0.4 and 0.3 metre). The frame-finder has cross-pieces, and the aperture control is now a turning knob. The camera back is secured by partly-metal catches (whereas those on the first model are all-plastic).
At least under the Formaplex brand, a back for 135 film was available; simply a different back piece to clamp to the camera body with the same catches as the 126 back. A second front strip, with an alternative set of focusing lenses, was available as an accessory. A short description of the camera reproduced at Collection Appareils gives the dimensions of the camera, with the 135 back, as 140 x 128 x 108 mm, and its weight as 1080 g.