Strobe Failure – A note of caution
Wetpixel carries sad stories of underwater strobe malfunction or burn out while shooting (ref 1) but at times important details are missing, such as if the strobe was being fired in rapid sequence, in the water or in the air. This is important to know, as strobes overheat when fired rapidly in a row, particularly when out of the water.
The makers of underwater strobes clearly warn about this danger. For example, the Sea & Sea YS-D2 manual states:
"CAUTION. If the full flash has been activated ten times in a row, allow the product [the strobe] to rest for 10 minutes before attempting to use it again."(ref 2) and in the Inon D2000 User Manual we read:
"Do not fire the strobe on land except for functional check. Do not fire the strobe at short intervals during functional checks to avoid malfunction of internal circuit,"
"Never repeatedly fire the strobe continuously, for example, to test, discharge or refresh the batteries." (ref 3)
The reason not to fire the strobe rapidly in a row, even in the water, is that the high voltages used to charge and fire the flash tubes generate a lot of heat, which takes time to dissipate as the flash tubes are mounted at a distance from the outside cool water. The plastic bodies of popular strobes further help retain the heat. When fired in a row in the air, overheating and burn out are an even higher risk. One needs to keep in mind that underwater strobes are designed to work in cool water, 0°1 to 30° C, not in air.
Another warning from both Inon and Sea&Sea is to not aim the strobe downwards while firing, as it damages the circuits. This may be because an internal switch or similar device needs to be horizontal to work properly, but no reason is given.
Two suggestions for safer strobe shooting:
Shoot more deliberately and slowly, space the shots to give the strobes a chance to cool off.
Do not shoot in a row when out of the water.
1. Our strobe problem.
2. Inon D2000 User Manual,Type 2, Basic Operation, p 6.
3. Sea&Sea YS-D2 Instruction Manual, O3117, 2015, p E-23.