The camera as a 'time machine': still photography's unique asset. (Photocritique).

All four of this month's examples depend on freezing or blurring moments in time to express ideas about various forms of energy. It is no accident that these photos all appeared in stories related to energy in SCANA Insights, a magazine published by SCANA Corp., a Columbia, S.C., company whose products provide energy to consumers.

At a South Carolina Philharmonic concert sponsored by SCANA, Jeff Amberg, a freelance photographer, finds an explosive moment of triumphant energy expressed in the conductor's face and arms. Amberg freezes this action and reaction with a very fast shutter speed. It is full of controlled power and energy, an apt metaphor for the company that helped make this moment possible.

For our second example, freelancer Robert Clark uses a tripod and a very slow shutter speed, extending a moment in time to capture the flow of a stream as it cascades over small waterfalls. Clark's blurred image also speaks of energy and power. An accompanying story tells us that SCANA places its equipment under, rather than over, such streams, providing energy to its clients while also preserving the natural beauty of the environment.

The third example, a blurred image of a child dancing with her father, captures another extended moment in time. This picture originated in a SCANA subsidiary's TV commercial called "Giving Energy to Life." Because of the blur, the subjects are abstracted and can represent any of us. The interaction between the father and daughter speaks to quality of life and is indirectly linked to the products and services provided by SCANA. Its magazine used this picture across a spread to intensify the image's symbolic power.

Our final example brings a moment to us out of the past. We often use photos to overcome the limitations of our memories, and pictures made long ago can bring history to life again. Here, SCANA salutes an event that took place more than 70 years ago, long before most of us were born. A dam is under construction, and five earth-moving machines provide the backdrop for the two teams of mules in the foreground. Seven of the eight workers appear to be waiting for the photographer to complete a lengthy exposure before they go back to work. The eighth is not aware that he is being photographed and is little more than a blur as he strides down a hill.

These people have long since built the dam, and a lake now marks the spot where this picture was made. Yet because the camera can function as a "time machine," this image survives to remind us of a time and place that is no longer with us.