Project 1 – The instrument exercise 1.1
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’.
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.
Add the sequence to your learning log with the time info from your camera’s shooting data as your first image for part one.
On examining the histograms for all of the sets of exposures I can see that it has changed in every single shot. The addition of a tripod reduced the amount of difference but it did not eliminate it. The more inanimate the object the smaller the changes, for example in the photographs of the spider web it shows a much greater amount of change between the exposures. Presumably this is due to changes in light as well as movement of the web and leaves etc. The smallest amount of histogram difference is in the frog ornament photographs using a tripod. The tripod has steadied the camera so removing variations in the camera positioning and as the objects in the frame are both solid, the frog and the fence, the only movement in this shot would be due to the changes in light.