Birtac cine camera/projector

"Birtac" camera projector for 17.5mm film, made by Birt Acres in 1898; complete with handle, lens, two mantle holders and spool of positive film showing "Domestic Scene". The magazines hold 20 feet of film, sufficient for about 40 seconds of filming. The intermittent motion is of the 'dog' type.

Designed by the film pioneer, Birt Acres (1854-1918), this was the first piece of film-making apparatus intended for taking and projecting films principally for home use - the beginnings of what would become the amateur film market. It used 17.5mm film, which was produced by slitting standard 35mm film in half. the recommended turning speed was about 40 frames per second for which it was necessary to turn the handle at a steady rate of 3 revolutions per second. to help with this, a plumb bob was supplied of the correct length which when hung by its loop swung at the rate of 3 beats per second, helping to indicate the correct speed.

The Birtac was not successful. shortly after its announcement, a rival, the Biokam was announced in march 1899. this home movie outfit was marketed as a snap shot camera and enlarger as well as for moving pictures and was half the price of the Birtac.