Hi John
A couple more things to consider if you do go the compact route ...
- There's a substantial price difference (last time I checked) between the Canon housing and the next-cheapest option.
- For cameras with small lenses such as these Canons, the obvious way to go for wet lenses (should you decide you want a wide-angle lens) is the Inon AD-mount. These lenses are much easier to deal with than the M67 (67mm thread) mount lenses. But Inon do not support the Canon S60/S70, apparently because the native lens is so wide already that the adapter would vignette, and they don't want people to compain about that. (Having said that, I got an Inon AD_mount adapter from a website in Austria, and it works, although it does in fact vignette unless you zoom in a bit; but the result is still much wider than the native lens alone.)
- If you house an expensive camera, make sure your insurance is appropriate! Occasionally people DO flood these things.
- My observation on live-aboard trips is that dealing with the housing is much more fiddly with the DSLRs. But since I have never housed one, that's a bit of conjecture.
- I have personally resisted the DSLR route because of the size and weight of the whole setup (I already usually have to fast-talk my way out of weight penalties when I check in for dive trips!), and my presumption that's it's more complicated than what I do now.
- My other - equally important - reason for resisting the DSLR route is that I so much dislike the idea of not having a view of the whole scene - including whatever's happening around me - while I'm framing a shot. Different people obviosuly have very different preferences in this area. Without knowing your level of diving skill, I'd just suggest to be sure you don't initially give yourself too high a task loading in what is afterall a potentially lethal environment. My observation - based on watching other divers - is that a housed DSLR leaves you less spare attention for your dive situation.
I have a few S70 shots (only did a few dives) in the 200411 Bali Diving gallery here:
http://www.fototime.com/inv/36B23AC6067E711
Some of these used the Inon w/a lens or macro lens. Wherever I used flash it was a pair of Inon Z220s.
The "S70 Manta" subdirectory has shots taken by my girlfriend on her one-and-only dive (of that trip) with the S70 - she had ear problems and couldn't descend as recommened, so she was right up there with the Mantas. She used the Inon W/A lens.
Otherwise, in the "diving" subdirectory, the others are all my shots with the S70 (except the Mantas were taken with my old Oly5050, without a wide-angle lens)
(All the previous diving directories were taken with the 5050.)
HTH
-David
[edited the embedded link]