I have used the Olympus 5050 digital camera in the matching Olympus PT-015 housing for a while. With it large aperture lens (F1.8) it allows in plenty of light for the underwater environment. Unfortunately, Olympus don't make the camera or housing any more. The good news is I have a second camera as flood insurance. The camera is a bit old, only 5M pixels, but is still a "goodie"
The secret to using the camera underwater is simple.
Note the "OK" button on the rear. We will call the buttons around this "UP", "DOWN", "LEFT" and "RIGHT". Above the UP button is the "Quick View" button.
The Mode selector should be left on "P" for Program mode. Below the power switch is the Thumbwheel.
On the left hand side of the camera is the Flash button
Always use SHQ, Leave the Camera in Program mode, force the Flash on.
I have not had much success using the Macro mode. Good luck if if you want to use it.
Always use SHQ, Leave the Camera in Program mode, force the Flash off, Adjust white balance using your slate.
This is the Important bit - Keep re-adjusting your white balance as you chance depth or lighting conditions change. Adjust the white balance using your dive slate.
Since my eyesight is not so good, I have found it easier to just remember the sequence of keystrokes from power up, rather than trying to read the small screen. So, if things get messed up, I simply turn the camera off, and on again. I also remember on the mode selector switch, that the P for Program mode is next to the Green playback icon.
Good luck. Peter Hicks.