The camera is primarily the creation of an unknown Camerologist, with some assistance from Dr. Fritz Fredricks, (nicknamed Spidey at some point in his latter years, due to his appearance seeming to become more 'spider-like'). Fredricks, at the time young and greedy, wanted to profit solely from the camera, leading him to remove it from its place of development, restricting access of the item to his exclusive possession. Spidey clearly had intent to present it to society and claim it was his invention alone, likely bringing fame and fortune. The Camerologist, greatly angered by Spidey's insolence, utilised a spell from the Dark Arts (something he had either been born with the use of, or been taught to use to a masterful level, some time prior to the events shown), placing a curse on the camera: It would from then on, be indestructible, lasting potentially for eternity. It would appear to have (to those unfamiliar with its capabilities) the ability to predict the future (a conclusion that can be drawn from the content of the photographs it produces, which don't even necessarily show much of the content the photographer has photographed e.g. Terry Banks made a horrid face in his bedroom, but the picture showed him distraught at the baseball field). What it actually appears to do is alter the future to a guaranteed negative, with the new event involving any number of the factors exposed by the flash e.g. cars, streetlights, people (most frequently) etc... though the factor may be involved in a situation completely removed from the location the photographer took the picture in (its true manipulation of matter, time and space is unclear) More significantly than any other feature perhaps, it can only make BAD things happen!
It's only known natural function is being an instant Polaroid camera, producing exposures that fade into focus from a slot.
Conditions on its power
The evil camera cannot move on its own, and therefore must be carried around. As long as it stays well-hidden and unused, it is powerless.