Using Sound to Trigger the Flash for High-Speed Photography
Methodology for initial shots: I used the TriggerTrap device and flash adapter with my Canon 430ex II flash to capture images using sound as the trigger in the mobile app (iPhone 5s). The TriggerTrap app allows the user to adjust the sensitivity to sound to ensure that ambient noise does not trigger the flash. I set my camera (Canon 6d) in manual mode (or bulb mode) ensuring that my exposure is completely black and that all of the exposure will be a result of the flash firing. In some of my initial test shots there was some light spillage that resulted in ghosting; be careful to avoid this. The flash in the images below was on a light stand and was unmodified. I manually set my flash to a low power to ensure a fast flash duration.
(Above Image: Notice the ghosting resulting from ambient light in the scene)
The water balloon photos were created by filling the balloons with water and then blowing a little air in to make certain that a popping noise was created. I then hung the balloons from the basement ceiling and framed the image. I placed the flash on level with the balloon to the left of the camera. Once I had eliminated outside light sources, I experienced a 100% success rate capturing water balloon images. So far I highly recommend TriggerTrap to anyone interested in getting into high-speed photography.
Note: This post only address one of the many functions of TriggerTrap.
(Click image below to cycle through examples of water balloon images created using TriggerTrap)