ST-100 and YS-03 slave

In a different thread, I mentioned that I had two Z330s delivered, but found in the instructions that they could not be fired in parallel with a Y sync cable, which is the only connection I have from my Meikon/a7Rii case.  I returned the strobes.

Barmaglot suggested firing the second strobe off a fiberoptic connection, taking as input some of the light from the first strobe connected to the case by sync cable.

I have a Meikon ST-100 (fiberoptic and sync connectors) and a Sea&Sea YS-03 (fiberoptic connector only and TTL only).  I tried running the ST-100 in manual by sync cable and triggering  the YS-03 TTL with light picked off from the ST.

Case B.  The YS-03 tracked the manual ST-100 output.  ST-100 output about 11% higher than YS-03 along the normal.  Of course, angular coverage would differ.  In operation, only the ST-100 would have to be adjusted, and the YS would follow.

Case C:  Test of the ST-100 TTL setting.  RX100iv manually set for ISO100 and f/11 to push strobes to maximum output.  For the YS-03, there is plenty of output for normal orientation and the pulse is short (expected).  For the strobe rotated 90deg off normal, peak intensity is reduced (expected) and pulselength is increased (expected) as the camera tries to recapture as much light as possible.  For the ST-100 at normal orientation, short pulse would be expected, but long pulse is observed; and at 90 deg orientation, reduced amplitude (expected) with the same pulselength is obtained.  TTL mode for the ST-100 does not appear to work.

Conclusions:

I could go with my existing ST-100 and YS-03 and accept unbalanced illumination.

I could run two ST-100s in manual mode (balanced illumination) with a Y sync cable if they don't damage with that setup.  Considering their electronics may not be sophisticated, that could be an option.  Maybe cheap enough to be worth the risk. Y cable $150, second ST-100 $250.

I could order two Retras with their sync-fiber converter.  Run manual until the UW-Technics electrical-optical converter becomes available.

Test layout.  The scene was the corner of a cluttered work bench. Distance from strobe and camera to corner about 1 m.

Two setups tested. B-YS-03 triggered off light from ST-100 in manual.

[A.] ST-100 output in manual mode. Set refers to strobe setting, know rotating clockwise for increased output. [B.] Results for setup B.  YS-03 output for settings in A.  YS-03 tracks ST-100 manual outputs.  [C.]   Results for setup C.  YS-03 and ST-100 facing along normal and at 90 deg to normal.