1.1 The Instrument.

Instructions:

Take three or four exposures of the same scene. Don’t change anything on the camera and keep the framing the same.

Preview the shots on the LCD screen. At first glance they look the same, but are they? Perhaps a leap moved with the wind, the light changed subtly, or the framing changed almost imperceptibly to include one seemingly insignificant object and exclude another. Time flows, the moment of each frame is different, and, as they saying has it, ‘you can’t step into the same river twice’.

Now bring up the histogram on the preview screen. The histogram is a graphical representation of exposure – the camera’s sensitivity to light. As you page through the images you can see small variations in the histograms. Even though the pictures look the same, the histogram data shows that in a matter of seconds the world changes, and these subtle differences are recorded by the camera. If you refine the test conditions – shooting on a tripod to fix the framing, moving indoors and closing the curtains to exclude daylight – still the histogram changes. Probably some of the changes are within the camera mechanism itself; still, the camera is a sensitive enough instrument to record them.

Here are my three exposures of the same scene. These images were taken on a local coastal walk 6 miles from my home overlooking Bedruthan steps beach. In the first photo you can see a bird that was flying across my view, in the other photos the bird had gone out of sight.