90mm macro lens
For this high-speed triple exposure of 3 separate clear lit light bulbs
I used the tricolor (RGB) filter technique.
A light bulb socket was firmly mounted to a table over a black backdrop
with the camera mounted on a tripod and sandbagged to keep everything
in registration for all 3 exposures. A pellet gun was mounted to a V support
with the tip of the barrel exactly 48 inches from the bulb for all 3 exposures.
A sound trigger was placed close to the pellet gun to pick up the sound
of the gun going off. The sound
trigger was connected to the input of a delay module who's output in turn was connected to an electronic
cable release. By adjusting the delay to correspond with the pellets
piercing the lit light bulbs I captured the filaments still lit with the
hot gasses escaping before the bulb actually
exploded. I recocked the shutter after each exposure and changed the
bulb and filter 3 times. The repeatability of both the electronic and
mechanical timing was critical.
Note: This shot could not have been
achieved using open flash technique as the lit bulbs would have totally
washed out the image.