For most of the shots I've made I used a Canon Ixus 800 IS
- also called the Ixy 800, or SD 800 - depending on where you buy it - Canon has the craziest naming scheme for it's models.
It is a really nice camera in it's own right - with out the underwater housing, useful for places I wouldn't take my Nikon DSLR. A couple of years old now - at 6 mega-pixels it won;t be top of the range. If I were to buy now - I'd look for the Canon Ixus 950IS - or go pro and buy an underwater housing for a DSLR
The case Canon WP-DC5 - specifically made for this model. Why would I recommend this combination:
1. Cheap and high quality. (I paid about $450 for both back in March 2006)
2. All the controls (except print!) are accessible with the underwater housing.
3. Reasonable video functions - terrible audio though!
4. Good camera to have even without the underwater housing.
One caveat with underwater cameras - you have to get the housing and camera at the same time - or risk not being able to get one or the other at a later point. I had a Ixus 700 and housing but unfortunately the camera died due to getting sand into the lens mechanism... several unfocused grinding shots later... I searched Kuala Lumpur for another Ixus 700 but just couldn't get one. I had to buy the bundle or not take photos and videos underwater while diving everyday for about 6 months...
Tips for Getting the Best from this combo
Looking after the camera
• Be very careful with the seal - don't stretch it - put a little silicon grease on it before each batch of photograph taking - make sure there is no debris on it.
• Keep the lens and underwater housing clean!
• Before diving keep the camera in the housing in a bucket of water in the shade... it will keep the camera cool and avoid it steaming up on the dive
• Heat is your enemy - the camera will steam up in the housing - so don't put it on bench in the sun!
• When not taking photos - turn off the camera - the battery generates heat...
• Use the underwater scene mode
• Never use the Zoom!
• Get close!
• Use the macro function when at about 15cm
• Use the flash for macro shots - make sure the diffuser is in place
• Take lots of photos - consider the continuous mode
• Get really good at your buoyancy - get neutrally buoyant - and stay steady
• Take the shots horizontally at the subject not just from above
• Forget shots with flash if the subject is more than 50cm away.
• If the Viz is bad - you will be limited to close shots.
I'd also really advice getting good at diving before trying to take good shots - I think 30 plus dives should be considered - a few snaps of your fellow divers is one thing - but trying to get shots of macro life is difficult, in order not to damage the reef, and annoy your fellow divers you need to be in full control.
Hope that helps and inspires!