The camera is made up of what we might think of as three distinct parts(mediums, even): the lens, the shutter and the light-sensitive surface. When theories privilege the lens it is usually in relation to the depiction of space and the conventions of realism determined by linear perspective and optics. Here we are in the realm of resemblance and iconicity, where the origins and the essence of photography are located in the /camera obscura/. When the shutter is invoked it is in relation to time and and duration, and photography’s origins and essence are located in the desire for arrested vision. When the light-sensitive surface is invoked it is usually in relation to the question of contact and touch, locating origin and essence in the shadow or trace.

— David Campany, A Handful of Dust