Foxfish, are you sure you are setting the strobe correctly? It can be tricky with the S100 so hopefully your dealer explained to you how to set the strobe correctly. Also, in TTL mode the Ys-01 needs to get a good solid transmission from the fiber optic cable. The bare cable should work fine. Good luck! Let me know if you have any more questions, I've used this same setup many times - Scott
Dealer hasn't been much help with after sales service. I do know that the strobe TTL setting is dependent on whether there is pre-flash. While underwater both DS TTL settings were unreliable so I ended up on the manual mode as explained above.
I've since bought a Sea and Sea L FO cable, snipped off one plug and bared 5 mm of the fibre optic cable. This works well, at least on the surface, but then so did the other.
If Recsea does a female adaptor for the Sea and Sea plug I'd be interested to know. Couldn't see it on the net.
I'm also having problems with the housing front ring control which I've set to adjust focal length in the Av and Tv modes. The housing ring slips as I turn it to change the focal length. This may be better underwater with greater pressure pushing the camera against the housing. Be interested to hear if any one else has the same problem.
When cleaning the housing, the small rubber grommets used for locating the camera come out of their socket. It appears that these grommets apply the pressure needed to make the necessary contact between the camera and housing front rings.
For those who haven't had much experience with strobes, they consume a lot of power. The YS-01 has four AA size batteries and after about 100 to 200 shots they're dead. I've bought a set of AA rechargeable batteries.
The strobe is mounted on a 5 inch arm connected to the mounting plate handle. I suspect that the back scatter is a result of relatively poor visibility, distance to the subject being too great and the flash exposure being too high. I did vary the position and direction of the strobe but this did not seem to help much. As a novice I'm sure there is room for improvement in technique, but it seems clear that using a strobe is no magic bullet to solving back scatter problems in relatively poor visibility. Visibility was about 8 m.
One aspect I want to investigate further is the difference using camera internal flash, a Sola 1200 photo light and the external strobe when shooting say up to 0.3 m (1 ft). On the surface the difference is not that noticeable.
Be interested to hear the modes people mostly shoot in using the Canon S100. Seems to me that the Tv mode is best. Set shutter speed to suit the shot and let the camera sort out the aperture and ISO settings. On the surface the camera does this well.
I do get some vignetting when shooting with the macro lens mentioned above on the lowest focal length.
To date as you can imagine I'm not exactly blown away with the new setup. The ability to adjust the camera settings is a big plus and the camera is at least as good as I'd expected. It remains to be seen whether these things are minor teething problems that will quickly evaporate with more experience. Time will tell. It will be interesting in a few months time to look back on the comments and see how things have progressed.
