I have the same camera/housing set-up as Pedro. Takes very good pix close up, but you'll get backscatter without an adjustable strobe from distances greater than about 3 feet. Just keep close because getting involved with stobes is a whole 'nother kettle of fish...

Another couple hints to keep the camera fog-free. Try loading the camera in an air conditioned room where the humidity is lower. Also, don't leave the camera constantly on while diving. The camera will produce heat which will only make the condensation worse. Cycle the camera on & off when you're ready to shoot. I use the silica packets too.

Best thing about the Canon s410/500 is that they're great topside cameras too. SO easy to use, compact, and they take digital video too. It's a home run.