Basic Underwater Photography Guide

Scuba divers on their first outings with a brand new underwater dive camera often return home to find their memory card is full of disappointing pictures. The underwater environment poses special challenges to would-be submarine photographers, but these are not hard to overcome for even the casual scuba diving shutterbug. By taking just a few extra steps, a novice diver can take pictures underwater at least as good as their conventional, land-based photos.

Problems
Light is the source of the two major hurdles to taking clear pictures underwater. The underwater environment is a dark place even in crystal clear, Caribbean-style seas, as water absorbs light much faster than air. This both darkens the local environment and rapidly absorbs color, with bright reds, yellows and oranges gradually disappearing into pink and tan. Taking vivid pictures therefore demands brightening up the subject of the photo, but pointing a light at the subject or using a flash is the cause of the second major problem for novice underwater photographers: backscatter.

Backscatter is the reflection of light off the particulate matter that floats in all but the clearest water. For a typical dive off the coast of North Carolina or California, one can expect a camera flash to produce a sprinkling of speckles on the image, as the light bounces off the sand and grit floating in the water and back into the camera lens. The result is a ruined picture. Therefore, the most elementary problem a novice underwater photographer needs to tackle is how to illuminate the subject without causing backscatter.

Use of Angles
The most direct solution to the condundrum of illuminating a subject without causing backscatter is to illuminate it indirectly. Look at the dive cameras used on National Geographic specials, which routinely mount lights on the end of long armatures. The purpose of these armatures is to point direct light at the target at an angle, causing any potential backscatter to reflect away from the camera lens. The result is an illuminated subject and little or no backscatter.

Of course, most casual divers have no wish to invest hundreds of dollars in adding a photographic light to their already-expensive underwater camera. A cheap, but sometimes awkward work-around is to use your own arm and a dive light in place of the photographic light source. A diver in a stable position can use a hold their underwater flashlight out at arm's length and point it at the subject, providing the necessary illumination at an angle. This technique does not work in even the a minor current, however, because that free hand is usually needed to hold onto an anchor (such as a rock or piece of shipwreck) and unavailable to point a dive light. In these cases, the diver's buddy can be recruited to serve as a light man, with the team sharing the resulting pictures.