I picked up a Pentax Optio W20 camera to do some testing with.
The W20 is waterproof up to five feet below water for 30 minutes.
The camera comes with 3X optical zoom and some amount of digital zoom. I de-activated the digital zoom as I don't like the feature.
The video option is crisp at 30 frames per second in 640 by 480. Filming underwater is amazing. You should wear goggles to make sure your pointed in the right direction. And guess what ... the audio works underwater as well. Just make sure you have great overhead lighting for the video to turn out. I don't recommend using the zoom in video mode as you can hear the motor in the video clip.
The camera functions well in low light. You just have to be patient with it and let it autofocus on its own. Don't expect to be able to take action shots in low light.
There is also a high speed continous shooting that takes about 5 pics continuously. It works great in with lots of light.
The macro feature is amazing. I took some pictures of my daughters nicknacks sitting on her window sill that was totally backlit from outside sunlight.
Overall I am really happy with the camera and I look forward to using it on the river this summer.
Teddy bear.
Little teddy bear.
Little teddy bear macro feature on head.
Little teddy bear in trunk.
Small items on shelf taken in very low light and flash. Notice that you can even see the dust on the shelf. My sister needs to clean.
Outside ice by side of road.
Outside ice by side of road maximum optical zoom.
Outside lifeguard chair in the ice.
Zoomed in at maximum.
River pics.
Outside playground set.
Video of Jenny Right-Side see a underwater shot hand rolling her boat complete with audio. Note 5.0 MB in size