Thursday, August 23, 2012

Center of the Perception


After the Prime Location– the Center of Perspective– has been selected the second dimension of editing that a photographer normally enters into is the direction into the universe that the camera is aimed. Before this choice is made, the camera is free to rotate in any direction, pivoting about the center of perspective. This pointing in space is the axis, or vector, that further defines the image to be created. Just as the location of the center of perspective is a choice of one spatial point out of the infinititude of possible points, the direction that the camera is ultimately to look must be a single choice out of equally infinite possible directions.

Direction of View, A
And as the point of perspective defines the center of the photographer's perception, so the direction of view of the camera will define the center of the final image, or the center of interest for the final observer of the photograph (this is part of the "what?" dimension of editing). While the point of perspective is the place the photographer is looking from, the direction of aim (direction of view) is the point infinitely far away that the viewer of the photograph will be looking toward. This is not to say that the major point of interest for the photograph's viewer is always the geometric center of the image, as that is rarely the case in reality. But it is to say that this is the cardinal reference point for the viewer– the point to which all items of interest in the image are referenced or related.

One could think of the point of perspective as the center of the perceiver (or the camera), and the direction of view as the center of the perception (the image).

Direction of View, B
 There are two rotational dimensions that comprise the camera's aiming direction. These are commonly called the elevation and the azimuth. The elevation is fairly obvious– this is how high above (or how far below) the horizon the camera is pointed. The azimuth, while not quite so obvious, is basically what "compass direction" the camera is pointed toward.

The three photos to the right may not be all that interesting from a visual standpoint, but they will serve to illustrate the issue at hand. Even though the camera's entrance pupil is at exactly the same place for each shot, pointing the camera in a slightly different direction drastically changes the composition and substance of the shot. And even much more subtle changes in the camera's direction than I have used here can still dramatically change the look and feel of the final photograph.

There is another part of this rotational editing that generally occurs at the same time as the direction of view. But unlike choosing the direction that the camera is aimed, this choice is nearly always by default. This is the orientation of the camera, or the angle of rotation between the bottom edge of the image and some reference plane in the universe (for instance, the surface of the earth).
Direction of View, C

Nearly always, the photographer leaves this to the conventional choice and doesn't even think about it. That, in itself, is a choice. Convention would declare that the bottom edge of the image should be parallel to the horizon– and that "down" in the image should conform to "down" in the real world. But there is nothing that says this orientation is the only useful, significant, or valuable orientation possible. It's just the most obvious. In fact, if this orientation is actually allowed to be anything within the 360 degrees of rotation, whole new possibilities of creativity begin to reveal themselves.

We saw previously that the point of perspective is defined by its location in space, and this location is  composed of three translational dimensions– how high, how far left or right, and how far forward or backward (or as the mathematician has it: the X, Y, and Z).

Interestingly, the vectors that define the aiming of the camera are also three dimensional. There is the single rotational dimension of the image's orientation, and then there are the two rotational dimensions (elevation and azimuth) that define the camera's pointing direction. These two sets of three dimensions (three translational and three rotational) comprise the complete complement of what the physicist or mathematician considers the six spatial "degrees of freedom."  These "degrees of freedom" are what give the photographer the freedom to choose any possible shot from the limitless possibilities.

Use your freedoms wisely and don't simply settle for the obvious. 

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