What the photographer taking the picture and the historian viewing it must understand is that while the camera deals with recording factual things and events that form the subject of the photograph, it only produces a perceived reality that is remembered after the thing or event has passed. While people believe that photographs do not lie, this is an illusion caused by the mistaken belief that the subject and the picture of the subject is the same thing. One is reminded of the written inscription on the famous painting of a "pipe" by the Cubist painter Rene Magritte that refutes what we believe we are seeing by saying "This is not a pipe." Indeed it is a painting of a pipe and not a real pipe in the same way that a photograph of a subject is both an artifact and a record of what the photographer captured with his camera from nature. Because we see reality in different ways, we must understand that we are looking at different truths rather than the truth and that, therefore, all photographs lie in one way or another. Today's technological advances in digital manipulation of images that the public sees regularly in photographs and films now only makes it easier to understand what has always been true.

If the scene selected by the photographer shows too much, he has only to isolate those facts (to lie?) that will best support the truth. The camera's lens records the trivial with such clarity that the interpreter of the scene must carefully select the clues which, because they make things real, act as important symbols more than as story tellers. If a photographer cannot easily record a concept such as the "social class" or "economic condition" of a family or community or region, he can record a partial view that will allow viewers to select details that will help illustrate the truths or lies he is intending to convey. Does the photographic image contain symbols that mean "poverty or plenty," "lower or middle class," "squalor or comfort?" (See Figures with Activity 1 and 2.) Photographs of domestic interiors can, with careful reading, include as much useful data to answer those kinds of questions as written academic descriptions or official reports and can also generate an emotional or intellectual response. What other details did the photographer capture, on purpose or by accident, that will help the historian identify the subject or decipher the circumstances under which it was recorded? Does a careful examination, perhaps with a magnifying glass, reveal names on street signs or store windows, advertisements on billboards or posters, fashions from clothing or hairstyles, dates from auto license plates or calendars, or other pieces of evidence that help make this image part of a story as well as a picture?

The photographer selects rather than conceives a picture by choosing what will be inside and outside the four edges of the frame in his camera's viewfinder. Those edges take things out of context and define the content of the subject. The image of a politician speaking to potential supporters could be perceived quite differently if the photographer took a tightly composed close-up view showing only an attentive crowd and the speaker or if he framed a larger view from the back of a large meeting hall that showed the same small group along with a sea of mostly empty chairs at a sparsely attended event. In this case what was left out of the frame was as important as what was included within its borders.

Unlike other kinds of visual records, the photograph is always made in the present time. The slice of time that the photographer preserves instantly transforms the present into the past. Another photograph taken a moment later is of a slightly different subject and is a different photograph. The camera, however, can serve as a time machine in a way that no other instrument of communication can, making it a valuable ally of the historian. Throughout photography's history, as the technology improved, the length of time necessary to trip a shutter or expose the film continued to shorten so that the blurs and shakes evident in the beginning gradually were decreased. Nevertheless, the process is still not instantaneous, and all photographs are, in a sense, time exposures. The photographer Henri Cartier-Bresson tried to indicate the importance of choosing the visually correct instant to make an exposure by referring to it as the "decisive moment." Is the picture of a steeple falling from a burning church the same as the picture of the burnt remains? Viewers should also ask themselves how an image would be historically different if it had been taken earlier or later. How differently would a photograph of street life look were it taken at first light before the morning rush hour or on the same street at mid-afternoon? How different the same scene in January or July or from decade to decade? When time is stopped it creates a slice of time, a picture rather than a whole story.

When the photographer is out of his studio and cannot move his subject, he must move his camera. His vantage point for seeing his subject can be from above or below, from in front or in back, and from any of the other angles we are now used to seeing, thanks to the creativity of photographers. Often the point of view calls attention to subjects or details that we might not have thought important otherwise. The foreshortening caused by the use of a telephoto lens, for example, can make a viewer aware of the seeming density of some urban architecture or traffic on a city street by making things look closer together than they appear with a wider lens or with the human eye.

from The Photographer's Eye by John Szarkowski, former director of the photography division of the Museum of Modern Art in New York.