I get a bunch of questions on how I get photos of exploding balloons and smashing light bulbs, so I figured I would just explain the entire process here. I did these shots a few years ago, so I’m going from memory here. I had delusions of getting shots of things like guns firing, smashing watermelons, and such, but I never got beyond popping balloons, smashing light bulbs, and shattering glass jars. Maybe someday I’ll try it again.
What you need:
- Soldering equipment and soldering skills
- An SLR camera and the know-how to use the manual mode of setting aperture and exposure
- An old flash that you don’t mind ruining by soldering wires to it (or you can rig up paper clips onto the contacts and avoid solder to your flash)
- Some sort of tape deck or other audio equipment that has a microphone input (preferably with an input sensitivity dial) and an output
- A microphone (piezoelectric) that fits the jack on number 4
- A Silicon-Controlled Rectifier (SCR) from an electronics store
- A pitch black dark room
- Something to photograph that explodes making a loud noise
To do this, you’ll build a circuit that takes sound input from the microphone and sends a signal to fire the flash. The photographs are made by opening up the shutter on the camera in a dark room and exploding/smashing the object to be photographed which triggers a flash, thus exposing the image to your film or camera’s sensor at the precise moment of the sound.
First, you’ll need to cut a cord with an audio plug (that fits into the output jack on your tape deck or amp). Splice the two wires as shown from the +/- in the AMP part of the diagram. The tip of the jack is the positive and you’ll need to use an ohmmeter to figure out which of the two wires that is (or just take a 50/50 chance and reverse it if it doesn’t work the first time).
Your SCR has three gates, labeled C, A, and G. Wire and solder everything up as shown in the diagram. The positive on the flash is the contact on the center of the flash shoe and the negative is the rest that surrounds the flash shoe.
I used an old tape deck that I had to force to take the signal from the microphone by putting in a cassette with the little protect tab in place and hitting record and pause to get it running. From there, I could adjust the input dial to my liking.
Once you have it wired up, you can test it out by powering everything up, including the flash, and clapping your hands. The flash should fire with every clap.
You’ll then need to figure out how much delay you want between the exploding sound and the flash firing. Sound travels 13.5 inches per millisecond, so, if you want a one millisecond delay, place the microphone 13.5 inches from the subject.
Now you need place the camera on a steady tripod, get your subject ready to smash, pop, whatever. The flash should be placed appropriately to throw the light at a good angle to the subject. The camera should be in manual mode. You’ll have to experiment with the aperture setting–I usually start with 4.5 and go from there. The shutter speed doesn’t matter because the shutter will be open longer than the entire exposure. You just need to give yourself enough time to open the shutter, explode or smash your subject, and then let the shutter close after the flash fires. I use four seconds. I keep my ISO set at 100.
Everything needs to be done in a pitch black room, since any stray light will enter the shutter while it’s opened and waiting for the flash to fire. Once you have the lights out and ready to go, have a little flashlight in hand to practice what you need to do so you’re prepared to do it in the dark. Then it’s lights out, shutter open, subject exploded as flash fires, shutter closes, lights back on. Have fun.
Here are a few of mine: