Four Detective Cameras, 1889-1908.

UNSPECIFIED - JULY 18: From the 1880s, hand-held exposures became possible for the first time because of the introduction of gelatin-silver bromide emulsion plates. This prompted some manufacturers to make cameras disguised as, or in the shape of, everyday objects known as 'detective cameras', designed for taking candid shots without the subject being aware they were being photographed. The Goerz Binocular camera (1908) doubled as opera glasses; Houghton's Ticka camera (1906) looked like a pocket watch; and the best-selling circular waistcoat camera by Stirn (1889) was designed to be concealed inside a waistcoat. The Fallowfield Facile of 1888 was disguised as a wooden box, parcel or case, complete with straps and a carrying handle. (Photo by SSPL/Getty Images)