Photography offers us two stories about the making of photographs. One, call it the "frozen moment of life," is associated with photojournalism, street photography, candids, and snapshots. It capitalizes on modern photography's ability to capture some part of the way the world looks in a given place and instant ("modern" because you need decently fast emulsions and sometimes good flash). The photographer may take many exposures from numerous angles and lens settings, but she will look for and try to seize "the decisive moment" in which the fullest significance of the scene is manifest. There can thus be only limited planning; graininess, high contrast,cropping which breaks objects, and blur give authenticating testimony to the unplanned "catching" of the unstaged life of the moment.
The alternate story of the scene of taking photos contrasts on most of these points, bringing it closer to studio-composed oil painting. Here nothing is left to chance--nothing occurs by chance--and the viewer may ponder as long as he wishes why this or that detail is exactly as it is. It is a tableau vivant . There is still the difference from painting that all objects are seen in the camera's eye in one exposure, none in the artist's imagination only, so that the "actual moment of time" assumption is still maintained . This is perhaps why photography is so effective as a medium of pornography: the photographer must have been just a few feet away from the subjects who were doing exactly what you see to each other (or to themselves). (It is sometimes suggested that as people begin to realize what digital manipulation of photos can do--that the participants may never have been together in one place, exchanged looks, or bodily fluids--they will lose their appeal as a focus for fantasizing.)