The housing port is designed to accept color filter, wide angle, and macro options for 3.9-inch diameter ports. Light is absorbed very quickly as it passes through water. A subject will look darker, less colorful and somewhat grainy when viewed through even a few feet of water. The addition of a compatible wide angle accessory expands the camera's field of view underwater, providing the opportunity to get as close as possible to the subject and reduce the amount of water light passes through. The results speak for themselves - photos with the best color, exposure and clarity possible.