Painting with Light: Underwater Photo Fundamentals

Light is essential for all photography, and close consideration of light is particularly important underwater. Sunlight has the advantages that it's free and usually available. It lights up the entire underwater scene. However, sunlight fades and changes color rapidly underwater, with distance and with depth. Its effect also changes dramatically with camera angle and direction of the sun. For example, if you shoot straight up, perhaps to capture a view of a snorkeler finning along the surface, you are likely to get only a silhouette. If you shoot straight down, the astounding color and texture of a reef may disappear in the uniform "flat" lighting, and from the fading of reds and yellows. Natural light photos work out most easily if you stay relatively shallow (20 feet or less), shoot somewhat up from horizontal, and keep the sun behind you. But, other arrangements can work out dramatically well.

Lights you bring along, in the form of flashlights, strobes, or video lights, can fill gaps left by sunlight, and extend the possibilities and beauty of your photos. A bright underwater torch provides enough light to restore reds and yellows to a nearby subject. This does require aiming the torch and operating the camera at the same time, which can be challenging. A friend with good, shared communication skills can help, if both of you remain patient. For some angles, the sand can hold the torch in place. A "tray" with a camera mount, a handle, and a mount for your torch gives you a more flexible setup.

A tray can also accommodate a strobe. Strobes provide more light than most flashlights, with less battery drain. Most strobes have modeling lights, so that you can see where the strobe is pointed (which can be difficult to judge underwater). Strobe arms can bring light onto your subject from an angle. This is particularly important if the water is not perfectly clear. A carefully positioned light away from the lens need not illuminate fluff between lens and subject to create backscatter, where a light next to the lens will. Two strobes can fill in shadows; setting one strobe to lower power can bring out relief. The possibilities are endless.

Underwater photographs are commonly divided into two kinds: macro and wideangle. Macro subjects range from about the size of half a person, down to the smallest subject that your camera can photograph. Wideangle subjects range from about the size of a person, up to fisheye views that take in large scenes or groups of subjects. In both cases, it's important to get as close to your subject as you can: the water column saps color and light, and adds backscatter. Usually, a light or strobe is essential for macro work. For wideangle, a strobe can bring out color in a nearby subject, or add reflections from shiny subjects. Careful balance or strobe and ambient light is critical. Within, or beyond, these two categories are many others, including super-macro, which allows photography of tiny creatures, and close-up wideangle, which provides a closeup view of a creature in its environment. Usually, these require different lenses, as well as lighting. "Wet" adapter lenses provide some flexibility, but it's worth thinking about what you will shoot before you jump in. Of the various varieties, macro is more flexible and arguably easier to start with.

Whatever your rig, it's worth trying it out before starting that precious dive or snorkel time. You can learn a lot by putting the camera on a tabletop and making images of objects with different textures and colors, using the camera settings you plan to use underwater. How far away do you expect your subject to be? Where will you put your strobes? How narrow is the depth of focus? Be careful with lights and strobes: they are designed to be used underwater and can overheat under prolonged use in air. If you have access to a swimming pool, it's a great idea to make some underwater shots there, under controlled conditions. How buoyant is your rig? Which side wants to be upward? Stix makes non-compressible floats that can help with heavy housings or uneven buoyancy. Make at least 100 or so test photos. Usually the light in pools is clearer than in the ocean: walls and bottom are white, water is clear, and you are only a few feet down. Consequently, photography is easier. A plastic model dinosaur can be a good subject for macro. Kids make great subjects, and they and their parents may be pleased with your efforts.

Once you've taken photos, in the pool or in the ocean, you will want to edit them. Lightroom Classic is the standard package for underwater photography. It's easy to compare photos, and discard the ones that don't quite work out in favor of those that do. You can also adjust color balance, exposure, and a host of other settings that you didn't get perfectly underwater. If you're just doing a few shots from a vacation, you can get the free-trial edition. (Don't forget to cancel it). Or, you can get one of the cheaper packages that do some of the same things.

Underwater photography is like golf. I tried golf once, and it's extremely hard. A lot of things have to go right, for you to get the shot. Underwater photography is like that too. In both cases, every once in a while, everything clicks, and you think, "Whoa! I can be the star!" However, unlike golf, in underwater photography you are judged on your best work, rather than your average work. And, in underwater photography (unlike golf or scuba diving), the rules are meant to be challenged and sometimes broken.