Next was a wreck at 30m. As visibility wasn’t very pleasing (Oman / U.A.E.) and not much light down there, I took my strobes with me. And that was the right choice although the filter isn’t recommended in conjunction with strobe light.
30m, f2.8, ISO400, 15mm fisheye, no strobes:

My only complain about the Sealux 10D housing is that the ISO button isn’t accessable underwater. Shooting at f2.8, the image came out blurred. But I was surprised how good the filter works in murdy water in 30m depth! I better would have underexposed the image above and compensate during RAW conversion in order to avoid blurriness, like here:

Caught in the dark environment with ISO400, I switched on my strobes and fired one shot against the sand on the bottom for white balancing with strobe light. Following images with magic filter and strobe light:




I found the filter suitable for strobe wideangle work. My Inon strobes produce cold light which gets even colder when travelling thru water (wideangle). That means there was no strong whitebalancing required. I would even compare it to macro work with warm strobes (3500-4000K). However, proper colour fine tuning can be a bit tricky this way. When in doubt, I wouldn’t hesitate to take the strobes down as well, just for the case they are needed.
I’ve used the magic filter in conjunction with the Sigma 10-20mm and the Sigma 15mm fisheye. In my opinion, the fisheye is the preferred lens for filter work because it delivers so much better image quality if you have to open the aperture. I found the results quiet good even at f2.8 compared to the poor corners wideangles deliver behind a dome glass when not stopped down.
I think compact digicams have some drawbacks for ambient light & filter usage compared to DSLR cameas: higher ISO noise and less reliable AF with ambient light (filter blocks light too). But I still would recommend the filter. In good conditions, compact digicams should deliver great results too. Especially in conjunction with some wideangle conversion lens. This can be an affordable way to start underwater photography without expensive strobes in the beginning.
I just free dived once in order to see if it works, 10m:

I just put the filter behind the housing glass. This way, the filter would work with wideangle conversion lenses too.

Julian