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Motion freezing flash on a budget

A speeding bullet travels at a speed of about 850 meters/second or 2800 feet/second. In half a microsecond, the bullet travels about 0.425 mm.

The original high-speed flash was the EG&G 549 Microflash, and air-gap flash designed by Harold Eugene Edgerton. It delivered a flash duration of just half a microsecond (500 nanoseconds, or 1/2000000 second). This is about 80 times faster than a xenon flash, and fast enough to capture a reasonable sharp image of a speeding bullet or a bursting balloon.

However, The EG&G units are now aging and very hard to find. A replacement unit, the Spot 500 ns Flash, is manufactured by Prism Science Works, but these are not cheap. The cost of a basic unit is about USD 3300.

Recently, I've come across DIY projects posted on the Internet where hobbyists have built their own sub-microsecond flash for just a few hundered dollars.

Sub-microsecond means that the flash duration is less than 1/1 000 000th of a second or less than 1000 nanoseconds.

Read more about how to build your own air-gap flash in the blogs of Maurice Ribble, Johannes Eriksson and Niels Noordhoek.

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