Stroboscopic

Glenn Lawyer · Issue 57, Nov/Dec 2010 · pp. 60–62

Products mentioned: Canon 7D, Inon Z-240, Aquatica housing, Tokina 10-17mm, Canon 100mm macro lens

Tired of taking sharp, well-lit shots, I decided to move into new territory. Buried in a sub-menu on my Canon 7D was the option to set the on-board flash to “multi-flash,” an option which optic cables would eagerly pass on to my Inons. Stroboscopic! Some thought and a quick experiment in the kitchen taught me the first step of this new-to-me technique. Long exposure (0.5-1 second) with (almost) all of the light in the exposure provided by the strobes. The strobes themselves had to recycle 3-5 flashes in under a second without overheating. This meant low power; throughout my experiments I kept the right had knob between 2.8 and 4 (call it 1/4 power). Time to take it to the pool. Wide angle lens, medium aperture. For a subject, I used a convenient twig to moor a plastic squirt gun to the bottom. My technique was simple. Strobes in close to the dome. Subject-to-camera distance such that the…