Rarely considered in its own right, the camera obscura is an appendage of photography and cinema. This thesis examines the camera as an apparatus, rather than a simple device. What is the world of the camera obscura and how does it raise the problem of the relationship between reality and representation? What kind of thinking does it generate, what concepts does it imply? Here we have attempted to determine its spatiality and temporality and, more generally, to understand its philosophy.