High - Speed Ballistics
High-Speed flash photography of bullets requires a sub-microsecond flash pulse. Our flashes are
~700 nanosecond 10 Joule devices built by Prism Science Works. That's
more than 10kilovolts and 1000 amps. Not to be touched! The twin-camera stereo rig is set for a 1/4 second shutter speed and opened in the dark. The gun is fired while the shutters are open, and the flash heads (2) are triggered by a Mumford timer. The timer itself measures the speed of the bullet as it leaves the muzzle. Once the speed is calculated, an appropriate delay is computed so that the flash goes off when the bullet is at an accurately known position downstream (as long as it is in free air flight). This takes out variations associated with changes in muzzle velocity caused by dirt, different charges, gas pressure (for "air rifles"), etc. This is very fun stuff, but extremely messy. Be safe out there if you try it. Thanks to Ron ( www.studio3d.com ) for going the extra millisecond.