|F-21 spy camera from KMZ, designed for concealment|
image by Joe Lin (Image rights)
A Spy Camera is one designed to be hidden, so as to be used covertly, for spying. Such cameras may be disguised as something else - such as a packet of cigarettes or a handbag.
The term is often, more loosely, used for any subminiature camera. But some of these subminis were exlusively designed and produced for certain national secret servies, for example the Soviet F-21 which originally was made for the KGB in 1950. Later a civilian version was offered. The Swiss Biflex 35 was made in 1945, probably for a British secret service. It took 200 exposures on 35mm rollfilm. It had a Tritar 2cm F2.5 lens. An info video of the Bundeszentrale für politische Bildung about the former GDR's Stasi showed a special spy camera with thin extra long lens tube to make photos of private sphere thru holes in a living room's walls from the neighbour apartement.
Another kind of spy cameras are the aerial cameras of military drones and the cameras of espionage satellites. In the near future such cameras will also be carried by robots.
A similar term is 'detective camera', which was a common description of cameras of various designs in the very late 19th and early 20th centuries. Most of these were not concealed cameras, but less conspicuous than a conventional field camera (in particular, they are usually hand-held).