If underwater photography is a small niche in the wide world of photography, cave-diving photography is its obscure foreign cousin.
Challenges include taking enough light into very dark places, managing the risk of adding tasks to an already task-loaded technical dive and finding something to photograph when there's not a single colorful critter in sight.
On the other hand, the crystal-clear water, mysterious darkness and lure of the unknown can be a fantastic canvas for creating unusual and captivating images.
From my experiences, here are some tips and tricks for those thinking of taking a camera underwater while underground.
Photography is the art of playing with light.
In the ocean, wide-angle photographs catch the sunlight that filters down through the waves and weather.
With the background illuminated by natural light, strobe lighting brings color and definition to the foreground.
There are abundant creative options for mixing natural and artificial light sources to capture the underwater world — just look at the beautiful images being made throughout the world's aquatic environments.
When diving takes you to darker places, sunlight disappears from the equation. Despite what Hollywood would have you believe, the only lights underground are the ones you bring with you. Our eyes adapt easily to the dim environment, but camera technology is not yet quite as clever; powerful lighting is key to successful capture of cave-diving images. This is especially true when trying to photograph large and spectacular underwater chambers.
Underwater photographers know water filters out light, and divers see this on every ocean dive as we descend away from the sun. The practical application for photography is that strobe light doesn't reach very far. Depending on the strobe power and clarity of the water, the strobe flash may not reach subjects more than a few feet from the camera. In wide-angle reef photographs you can often see the transition where the colorful reef in the foreground turns to blue-gray coral in the background.
In reef photography, the way artificial light falls off with distance can be a useful tool for bringing the viewer's attention to the foreground subject. In caves, it works against the photographer. Without the less-detailed, ambient-lit backgrounds to provide context and scale for the object of interest, disembodied objects float in the black. Any subject farther away than the strobes' limited reach is lost in the darkness. The foreground subject could be anywhere, and conveying the beauty and grandeur of the space in which it floats is tricky.
On-camera strobes gently light the formations inTux-Ku-paxa cenote and trigger the strobes held by the divers behind
The solution? More light! Getting additional lights in the right places is crucial, and in some caves strobe positioning makes more of a difference than total power output. Photographers who venture into caves with two big strobes attached to their cameras may be disappointed to see their photos lack depth. When using only on-camera strobes, all the light in the photograph comes from a single point (or two points very close together) beside the camera. This straight-on lighting arrangement flattens details and textures, removes shadows and diminishes the third dimension.
To overcome this, move strobes away from the camera. Off-camera lighting is where caves allow real creativity — the uniformly pitch-black cave environment means the photographer gets to choose which parts of the picture to illuminate and which to ignore. Light from multiple, separate sources brings back the third dimension and lets the viewer see both foreground and background.
Off-camera lighting opens up a multitude of creative choices. Additional strobes can be placed to backlight key features, outline the entrance to a tempting side tunnel or light your buddies' expressions as they check out the scenery. If your dive team carries strobes positioned like dive lights in their hands, the images will look more natural and familiar to those who have been cave diving. Or you can go for a Hollywood look, hiding strobes behind rocks to make glowing walls. The options are limited only by your gas supplies, battery life and buddies' patience.
With no extra flash on the diver... With extra flash on the diver...
There are technological challenges in getting multiple strobes to fire in sync. The difficulties of shooting in complete darkness are obvious, but this is one area where darkness is a great bonus. Many underwater strobes have built-in sensors so they can be triggered by the flashes of other strobes or directly from the camera via fiber-optic cable. A flash from the strobe that's connected to the camera can trigger the off-camera strobes. The speed of light means the cascade of flashes moves faster than the camera's shutter, and all the strobes fire together. This can be tricky in daylight zones where sensors may be confused by sunlight flickering through the water. In darkness, however, sensors are much more sensitive to distant flashes of light and can be reliably triggered from farther away.
Built-in sensors are generally fixed to the bodies of strobes, and they may not always be ideally placed. Some strobes' sensors, for example, are embedded in the reflector, so if the strobe is facing a distant wall the sensor won't be facing the "trigger strobe" on the camera. This limits options for off-camera strobe placement because it may mean a strobe won't fire reliably when positioned as desired. Strobes that have omnidirectional sensors or allow use of a remote sensor on an accessory cord are a cave photographer&