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 leaf 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 the saying has it, ‘you can’t step into the same river twice’.
Set 1 – indoors
For the first set, I set the camera up on a tripod, in full auto mode and used a cable release. I took the sequence of three just a couple of seconds apart. The differences in the histograms are very minor, which I put down to noise – certainly nothing is different visually, so only the camera can tell!
Set 2 – outdoors
The second set was setup much like the first, but this time an outdoor scene. This time, there are actually some differences in the histograms – small, but they are there. There was a very small amount of wind movement and some cars in the distant background – not much, but obviously enough so that the histogram shows the differences.
My learning point from this short exercise is that even under quite controlled conditions, the world insists on changing! The differences may be subtle, but they are there.