Pictures are flat objects that contain pigment (either colour, or monochrome), and are very different from the objects and scenes they represent. Of course pictures must be something like the objects they depict, otherwise they could not adequately represent them. Let’s consider depth in a picture. In a picture, it is often easy to find cues relating to the depth of a scene. The depth-of-field often manifests itself as a region of increasing out-of-focus away from the object which is in focus. Other possibilities are parallel lines than converge in the distance, e.g. railway tracks, or objects that are blocked by closer objects. Real scenes do not always offer such depth cues, as we perceive “everything” in focus, and railway tracks do not converge to a point! In this sense, pictures are very dissimilar to the real world.

If you move while taking a picture, the scene will change. Objects that are near move more in the field-of-view than those that are far away. As the photographer moves, so too does the scene, as a whole. Take a picture from a moving vehicle, and the near scene will be blurred, the far not as much, regardless of the speed (motion parallax). This then is an example of a picture for which there is no real world scene.

Photography then, is not about capturing “reality”, but rather capturing our perception, our interpretation of the world around us. It is still a visual representation of a “moment in time”, but not one that necessarily represents the world around us accurately. All perceptions of the world are unique, as humans are individual beings, with their own quirks and interpretations of the world. There are also things that we can’t perceive. Humans experience sight through the visible spectrum, but UV light exists, and some animals, such as reindeer are believed to be able to see in UV.

So what do we perceive in a photograph?

Every photograph, no matter how painstaking the observation of the photographer or how long the actual exposure, is essentially a snapshot; it is an attempt to penetrate and capture the unique esthetic moment that singles itself out of the thousands of chance compositions, uncrystallized and insignificant, that occur in the course of a day.

Lewis Mumford, Technics and Civilization (1934)