Go out with a bang
James Paterson explains how a simple dongle can transform your phone into a sound trigger, allowing you to capture split-second action in stunning clarity
Learn how easy it is to photograph an exploding water balloon
High-speed photography enables you to capture moments that are imperceptible to the naked eye. You’ll need a few bits of kit for it, but you can get great results with a surprisingly simple setup. The most important factors are precision and speed: you need to capture the exact moment the action occurs, and to use an exposure that’s fast enough to freeze the motion.
A sound trigger is ideal for capturing any action that creates a noise. When the trigger detects the noise, it will fire the camera shutter or Speedlight, giving far more successful results than you’d get if you attempted to trigger the shutter by hand. We’ve used a sound trigger here to capture an exploding water balloon, but you could use the same technique to freeze the motion of any high-speed action that creates a pop or bang.
You might think sound triggers are expensive, but there’s a great gadget from Triggertrap that costs just £23 ($35) that pairs your camera or flash with your smartphone, enabling you to use your phone’s built-in microphone, camera, clock and vibration sensors to trigger your D-SLR.
Triggertrap’s D-SLR attachment is fine for most uses but, as with most triggers, there’s a slight shutter lag. For high-speed photography, that split-second makes all the difference. Luckily, Triggertrap has an extra flash attachment that connects your phone to your Speedlight rather than your D-SLR, eliminating shutter lag.
Flash is ideal for high-speed photography. The burst of light is incredibly fast, particularly at a low power setting. When set to 1/128 power, the Nikon SB-910 Speedlight we used has a flash duration of 1/38500 sec – fast enough to freeze the action. The problem is, we need the camera’s shutter to be open when the sound trigger fires the flash, but we don’t want any ambient light to creep into the exposure. The solution is to take the shot in total darkness. This way, you can open the shutter for as long as you need to, and the only illumination will come from that incredibly fast burst of flash. Here’s how it’s done…