Either (1) photography of psychic or paranormal phenomena such as ghosts, spirits, and fairies; or of cryptozoological or mythic animal species; or of questionable technological wonders like flying saucers; or (2) photography claiming to have been produced by psychic or paranormal means, as for example in thoughtography, kirlian photography, or aura photography.
When photography was first presented to the public in the middle of the 19th century, experts were quick to exploit the processes to produce paranormal phenomena. As early as 1856, prints of ghostly looking ethereal figures sitting next to the person being photographed were being sold as joke novelties. Nineteenth-century Scottish physicist Sir David Brewster, who was famous for his law on the polarization of light, wrote explaining how this was done by removing the would-be ghost part way through the long exposure time needed in those days. Nevertheless, for those who did not care to accept this explanation and for others who found it a profitable field to exploit, there grew a belief that “the camera cannot lie,” and so photographs of many alleged paranormal entities or events were presented as firm proof of their existence.