The Underwater Digital Camera Needs Light, Too
While it may seem ok to seal your everyday camera in plastic and dive in water, there is more to being an underwater digital camera than being waterproof. If you are swimming underwater and open your eyes, you should notice that not everything is positioned where you think it should be. This is the result of the refraction of the sunlight as it passes through the surface of whatever body of water you are in. Lake, swimming pool or ocean makes do difference, as lighting under the water is going to produce different results than the light on the surface.
With an underwater digital camera the light is reflected off the object being photographed and it doe not always travel a straight line. Most quality units adapt for the difference in the light allowing an underwater digital camera to accumulate the light reflected off the image as though it were traveling straight. Additionally, the further down under the water you go, the less light is visible as it is shielded from the sun's rays.
Many areas of water appear clear on bright sunny days and if you think about a time you stood nest to water that appeared to be really shallow and wasn't, then you will have some idea of the technology needed in an underwater digital camera to capture pictures without them appearing to be blurry.
Verify Camera Can Go As Deep As Needed
Another common misconception about an underwater digital camera is that they are all created equal. The reality is that different manufacturers design their cameras to be protected from water intrusion at different depths. Many listed as being waterproof will also include the depth at which they are safe from damage.
An underwater digital camera designed for depths down to 10-feet, probably will not take on water at 15 and possibly even 20-feet, but the camera is ruined at any depth greater than 10-feet, the manufacturer's warranty is invalidated. Those with a penchant for taking underwater pictures should make sure their underwater digital camera is rated for the maximum depth to which they intend to descend.
Whether the visual correction is done through the underwater digital camera optics or through software built into the system, taking pictures underwater is more involved than making sure the inside of the camera does not get wet. If you use a flash, you will have a picture of a sudden bright spot. Available lighting is the best source of illumination, but when necessary a steady light source is recommended.
