The London-based Purma Cameras Ltd. was created in 1935. Its name derives from a combination of the founders’ names: Tom Purvis and Alfred C. Mayo. The company produced Purma cameras from 1936 to 1959, except when production was suspended during World War II.

“The cameras of the Purma brand were 127 roll film viewfinder cameras with innovative gravity-controlled shutters, based on the company’s patents of 1935 and 1936, designed by founder A.C. Mayo” (source).

There were several models: the Purma Speed (introduced in 1936), Purma Special (1937), and the Purma Plus (1951–1959). While the Speed had an enameled metal chrome body, the Special was made almost entirely of Bakelite, and the Plus was made of aluminum. The Speed had a six-speed shutter (1/25–1/200) and a flip-up viewfinder. In 1952, the company filed a patent for a fourth model, the SAMA, but it was never put into production.

The Special was the most common model. It produced twelve 1.5-inch (38 mm) square pictures. An unusual feature was “a solid metal, curved focal-plane shutter with three speeds, controlled by a weight, which varied the slit width. The shutter is cocked using a pear-shaped lever on the top edge, above the lens; the slit width/shutter speed depends on which way up the camera is held. Horizontal gives medium speed, vertical with winding knob down gives slow, and vertical, knob up, fast.”

When held horizontally, the exposure time was 1/150 second. Held vertically with the winding knob down, it was 1/25 second; and when held vertically with the winding knob up, it was 1/450 second (Cameras From Daguerreotypes to Instant Pictures, Brian Coe, 1978, p. 129).

“Although the shutter was ingenious, its construction caused the camera to be very big in relation to its small picture size.” A Beck Anastigmat f/6.3 lens was housed in a sprung telescoping mount covered with a screw-on lens cap.

Unlike most cameras, the shutter release is on the photographer’s left, and the case opens upwards, not from the back forward. The removal of the screw-on lens cap causes the lens to spring out of the camera body. The plastic optics in the viewfinder are reputed to be the first use of plastic optics in a camera.

According to the online description, the book by Richard W. Jemmett has “all the information you might ever need on Purma cameras, including the manuals” (source).