With the Canon WP-DC28 waterproof case for the Canon PowerShot G10, you can use your digital camera to take underwater shots at depths of up to 130' (40 m). Of course it's also ideal for taking worry-free pictures in the rain, at the beach, or on the ski slopes.
You can use your camera's internal flash for lighting purposes. Or, use the internal flash to trigger a slaved external strobe like those made by Fantasea, Sea & Sea, Ikelite, or Sealife. The camera has an underwater white balance setting for available light photography.
