Does anybody have any first hand experience of these items?. I'm working on a project within which it would be nice to include a brief underwater sequence, and see these units as the most cost effective way of doing it. I'm looking at the SPK-DF4/DF5 for the trv900, or i might get a SPK-TRC and try and pick up a cheap second hand D8 cam from somewhere. I'm intending to set focus (hyperfocal, wide angle & just shy of infinity focus) and exposure before putting the camera in the housing (by metering off a 15% grey card placed at the depth I'll be filming at from above the water), I'm more concerned about things like fogging and seal reliability. How fluid are things like zoom control (I presume these go through a lanc?).