Am I kidding myself?

Right,

I'll preface this with the caveat that I'm a diver who's gotten into UW photography, not the other way around. I've been diving for about 15 years, but only taking pics for less than 2. I've recently got to the point where I'm using tmx on my ccr, so there will probably be 90-100m wrecks in the next 6-12 months or so (this isn't to sound impressive, I realise just how small this particular fish in the pond is ). I'd love to take pics up to the limit of the capabilities of what is around, and affordable (in relative terms). I'm currently using an olympus 8080 in Ike housing.

The problem at this point seems to be the obvious one: light available. Recently I had a weekend out in our local ships graveyard, diving on a couple of 55-60m wrecks. While it was a bit cloudy, vis would have been an easy 20m (v good for this area at that depth). I found on the bottom that the only way I could get enough light in for wide angle shots was to open the aperture right up (max f2.4), shutter speed of 1/6, and finally bump the ISO up to 160. I knew this would introduce some grainyness, but it was the first time I'd had to go that far. Any slower shutter speed would have made the divers just too blurred, and frankly without a tripod it was hard enough as it was at 1/6s. In the end this was a pretty typical image at ISO160:

diver on wreck @ 160

and ISO 80

diver @80 ISO

They're near to being useless at 160, and noticable at 80. I had similar experience up the back of some sinkholes near here.

So, after having a chat to a friendly photographer buff, the only conclusions I came to were that I can either get a tripod and ditch the idea of having divers in shots, or try the whole DSLR thing.

So, am I kidding myself? Is the extra light sensitivity of the DSLR going to help me take images of deep wrecks, and natural light pics of caves? Or more to the point, is the difference that great? FWIW I've been looking at Canon 30D's. Wrecks and caves aren't my sole interest, as a marine ecologist I'm a big fan of living stuff too, but that seems to be the limiting side atm.

As an aside, what are the options for DSLR housings with good depth ratings? I've vaguely looked in Aquatica, Hugyfot, Sea and Sea.

TIA

If you're looking for good high ISO performance the 30D is a good choice. You'll probably get around 3 stops better performance over the 8080.

The image quality of the 30D, 20D and 350D are almost identical. The lowest cost is 350D if you can find a housing for it at that depth rating that you want. The Aquatica 20D is probably good enough for 100m. Check with them. Their email is info@aquatica.ca .

There are a few things that can help with your particular needs:

1) As Herb mentions, a DSLR with a good noise-to-signal ratio will allow you to boost the ISO without introducing too much noise.

2) Using long exposures, potentially with the introduction of a tripod (see other threads on Wetpixel) would help

3) Selecting a bright, prime wide angle lens for your DSLR will also help

4) Shooting RAW instead of JPEG, and boosting the signal 1 or 2 stops during post-processing is also possible

5) And if all else fails, sell a kidney and get one of those monster HMI lights

One more option is the Olympus wide angle lens and Ikelite dome port:

http://www.ikelite.com/web_pages/8080domelens.html

You may want to check out The Deco Stop ( http://thedecostop.com )

It's a technical diving forum and I've seen a few threads from members who've taken their P&S housing well beyond the advertised depth rating.