Question Sea frogs sf-01 missed trigger?

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chris123

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Hi everyone,

I am new to underwater photography, after upgrading from a GoPro to a tough TG 7 with sea frogs housing and one sea frogs sf-01 strobe, and the standard sync cable that the strobe comes with.

I tested the setup in a lake and above water for just a few pics and it seemed to work fine, but now at my first diving holiday I had quite a lot of incorrect triggers where the strobe triggered too early or late and the image was dark.
In some cases, the strobe did not trigger correctly for 5-6 pictures consecutively, and sometimes just occasionally, but in total I had 20-50% wrong triggers.

I use the underwater or P mode with flash set to RC.
I noticed, it does work better (90% correct) when I set to full flash mode on the camera, but then the recycle time of the camera flash goes up to 2-3 sec (while recycle time on the sf-01 is about 0.5 sec).
Setting the flash to LM mode underwater seemed to temporarily fix the issue, too.

Any idea what could be the cause of this issue?

Many thanks for your help in advance!
 
RC is Olympus-brand TTL which, as I understand it, fires a series of pulses to tell the flash how to operate exactly. In order to operate properly with this mode, you need a strobe that understands it, such as Sea & Sea YS-D3 Duo (the non-Duo models of the same strobe don't have this capability). SeaFrogs SF-01 is a manual-only strobe, so to operate it properly, you need to set the camera flash to manual, the strobe mode knob to single lightning bolt, and the strobe power knob to the desired intensity. The camera flash power can be set to the lowest value that will reliably trigger the strobe; the exact value depends on the length and quality of your fiber optic cables. The 'LM' setting on mode knob is learning mode - when set to that, the strobe learns the sequence of pre-flashes emitted by the triggering camera and subsequently ignores all but the last of them, but, as I understand it, with the Olympus RC protocol, this sequence is not static, plus it introduces shutter lag and wastes battery charge, so manual operation is the proper way to go.
 

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