I have a cannon Uc-1 8mm with an underwater housing that has proven most adequate. Ive used in both salt and freshwater never in depth more than 15 feet Obviously they don't work well in turbid runoff conditions but I'm sure some of the high end digital units could work the magic even then. One draw back to the "handy cam" with under water housing is the back ground noise of the camera motor, it seems to be the same for alot of the hobby type units but if you buy a video capture board you will have the ability to edit the sound and fix that little annoyance.