Eric H Cheng. Focal Encyclopedia of Photography: Digital Imaging, Theory and Applications, History and Science. Editor: Michael R Peres. 4th edition. Amsterdam: Elsevier, 2007.
Introduction
Underwater photography covers the range of all still and motion picture imaging below the surface of the water, from single-use, waterproof, and disposable cameras to unmanned submersibles at the bottom of the ocean. However, the term usually refers to underwater photographs taken by scuba divers in rivers, lakes, caves, and beneath the surface of the ocean.
Historical Background
German inventor William Bauer tried to take pictures through the portholes of a submarine he built for the Russian navy as early as the Crimean War (1853-1856). Most sources, however, credit English photographer William Thompson with taking the first underwater photograph. In 1856, he used a camera in a watertight box to take photographs of seaweed and sand in the waters near Weymouth, England. Other early attempts were made by Ernest Bazin (1860s), who tried to make photographs from within a diving bell, and Eadweard Muybridge (1870s), who used a camera inside a watertight container in San Francisco Bay.
Frenchman Louis Boutan is widely considered to be the father of underwater photography. In 1893, Bouton and a mechanic named Joseph David snapped the first, clear, underwater photographs in the bay near the coastal town, Banyuls sur Mer. To light their subjects, they used a magnesium flashgun developed by Chauff our.
In the early 1900s, Jack Williamson, an American journalist, photographer, and writer, invented a device that made underwater cinematography practical. Camera and crew worked inside a sphere connected by a long tube to a surface support-vessel. The first commercial motion picture adaptation of Jules Verne’s 20,000 Leagues Under the Sea, among other movies, benefited from use of the device; it soon led to improved housings for motion picture equipment.
In 1927, National Geographic published the first underwater color still photographs; they were reproduced from Autochrome plates by Dr. William Longly, an ichthyologist, and Charles Martin, a staff photographer. The development of the Cousteau-Gagnan aqualung generator in 1943 freed divers from heavy, cumbersome diving equipment and inspired them to design and build their own complementary photographic equipment.
In 1943, Jacques Yves Cousteau and Emile Gagnan developed the first, self-contained, compressed-air underwater breathing system, which used a demand valve to deliver pressurized air upon intake of breath. The Aqualung revolutionized diving, and gave photographers tremendous freedom to experiment with underwater photographic equipment.
Professor Harold E. Edgerton of the Massachusetts Institute of Technology worked with Cousteau. Edgerton’s technical innovations include photographic units capable of withstanding tremendous water pressure, cameras capable of taking 2000 35mm pictures at signaled time intervals, underwater electronic flash, and even a sonar (radar-like) device capable of positioning a camera accurately within a few feet of a sea floor 15,000 feet or more below the surface.
In 1957, also with Cousteau’s guidance, a Belgian inventor named Jean de Wouters developed the CalypsoPhot 35mm underwater rangefinder camera. This eventually led to the development and commercialization of Nikon’s Nikonos series cameras, which dominated the underwater photography market until digital cameras became commonplace.
Meanwhile, in the motion picture world, Al Giddings and Leroy French were taking underwater cinematography to a new level by designing home made housings out of a dive shop in San Francisco. In the 1970s, Giddings experimented with the use of dome ports, which were probably pioneered by Hans Hass. These were optimized for underwater and wide-angle optics and are now used universally by underwater photographers. Other pioneers in deep water, underwater exploration and photography are Emory Kristof and Chris Nicholson, who used remotely operated vehicles (ROVs) to produce images and video documentaries of deep shipwrecks and the bizarre life found around deep sea thermal vents. Engineers and researchers are now experimenting extensively with autonomous unmanned vehicles (AUVs), which are capable of self-navigation and multiple waypoint missions without remote pilot control.
Each advance in consumer-oriented movie cameras, ranging from the 8-mm film cameras of the 1960s to more recent, high-definition video, have been accompanied by advances from manufacturers of underwater housings. Almost any respectable camera can now be used underwater. Camcorders are housed for underwater use in resin, Plexiglas, and aluminum housings from companies such as Gates, Sea & Sea, Ikelite, Light & Motion, and Amphibico in the United States and Canada. At the high end, underwater videographers and cine-matographers use broadcast-quality Sony HD camcorders and housed IMAX and IMAX 3D cameras.
The late 1990s signaled a new era of photography with the release of compact digital still cameras. The digital age broke the 36-frame barrier for underwater still photographers, who no longer had to surface after shooting a single roll of film. The release and widespread adoption of 6 megapixel digital cameras in 2002 was the turning point in the transition from film to digital in underwater imaging. New digital cameras are quickly adapted for underwater use almost as soon as they appear, and only the dedicated few prefer film.
Challenges and Opportunities
While underwater photography opens new horizons, it also poses a number of serious challenges. Photographers venturing underwater enter a new and hazardous environment. Underwater photographers must be expert scuba divers and may have to deal with life-support failures, cold temperatures, strong currents, aggressive wildlife, and bad visibility, not to mention water’s light-stripping qualities. Although visibility can approach 330m (1000 feet) in Antarctica, in more common destinations it is usually between 3 and 40m.
The most obvious challenge is keeping the camera dry, and this is usually done by enclosing it in a waterproof housing with a clear window and external access to its controls. However, because water has a much greater refractive index than air, a flat port reduces the lens angle coverage by a factor of about 0.3, so a 28mm lens becomes a 35mm lens and a 50mm lens becomes a 65-mm and so on. It also reduces focal range of a lens because the nearby distance is distorted by 33 percent, so a lens cannot focus as close as it would in air. A flat port also suffers chromatic aberration (color fringing) at the edges of the image as well as geometric distortion, limiting angular coverage. For all these reasons, dome ports are preferred for wide-angle photography.
Most wide-angle underwater photography uses hemispherical dome ports, which allow light to pass through to the camera lens perpendicular to the first optical surface, thus reducing chromatic aberration and distortion. The camera lens should be positioned so that the lens node (in practice, the diaphragm) is at the center of curvature of the dome, but this can be difficult to achieve in practice.
The curvature of the dome port introduces a lens of negative power in front of the camera, which makes objects appear further away. To compensate, it requires an equally strong positive lens (a close-up lens or diopter) on or in the camera lens. The strength of this lens is determined by the curvature of the dome and is often around 3 diopters; without it, many lenses would not be able to focus at all. Because some lenses can achieve focus underwater when used behind a dome port, corrective positive diopters are only used when necessary.
Some housed cameras do not allow for the use of a dome port; instead, they offer wet-mate wide-angle adapters, which are designed for placement in front of the camera’s lens, with water between the optical elements. Wet-mate accessory lenses are versatile because they can be attached and removed even when underwater.
Because macro lenses have long focal lengths of 50-200mm, close-up photographers are able to use flat ports without significant image degradation. Long focal-length macro lenses are common because so many underwater subjects are quite small, and they are often used in conjunction with diopters or teleconverters. Nikonos underwater lenses are corrected for the water interface effect, even for those using a flat port.
Water both absorbs and scatters light. Most of the scattering is variable depending on conditions, but the absorption is intrinsic and acts as a blue-green filter, first removing red light and then the remaining colors of the rainbow. Anyone who has taken a waterproof, disposable camera underwater knows that photographs taken without artificial lighting are predominantly green or blue. Nearly all underwater photography is accomplished with artificial, full-spectrum, continuous lighting (for video) or strobe lighting (for still images), which reveals the true colors of underwater objects. Because water also filters strobe light, colorful subjects in underwater photographs are usually photographed within 2m of the light source. Photographers also place strobes and lights on long arms that extend out as far as a meter from the camera because angled lighting minimizes backscatter, unsightly illuminated particles in the water column between camera and subject.
The most common films used underwater are Kodak and Fuji slide films in the ISO 50-100 range. Especially common is Fuji’s Velvia 50 film, which is popular for its vivid color and pleasing, deep blues. Digital photographers have the luxury of approximating different types of film during post-processing, but most shoot at a low ISO in order to minimize image noise.
Sometimes photographers choose to shoot without artificial lighting, allowing only ambient light for an exposure. The reasons for doing so are varied, but most of the time it is done to reduce drag while swimming or for specific, aesthetic reasons. Ambient-light photography often benefits from the use of color-compensating filters, which are sometimes designed specifically for underwater use. Digital and video cameras can, to some extent, use their electronic white balance settings to compensate for underwater color shifts.
These challenges also provide plenty of opportunities for creativity. Wide-angle scenes are exposed naturally, allowing ambient light to create dramatic backdrops for foreground subjects that are lit by full-spectrum strobe lighting. Macro subjects are usually exposed to maximize depth of field, often with aperture values of f/22 and smaller; the usual creative use of depth of field is difficult underwater. Cool, ambient light in a fluid, dynamic environment with strange distortions—and even stranger creatures—is unique, quite unlike any above-water studio.
In modern times, notable underwater photographers and videographers such as Howard Hall, Chris Newbert, and David Doubilet have produced a body of work that has inspired countless people into taking cameras into the watery world of lakes, caves, and oceans. Photographic imaging is also important in marine science, underwater archeology, and remote exploration of the vast expanses of ocean that are too deep for divers. However, to start taking underwater photographs, all one needs is a snorkel and an underwater camera with or without a strobe. For the more adventurous, a SCUBA diving certification allows the diver to go deeper for longer.
It has never been easier to take a camera underwater, but the challenges and opportunities remain. Advancements as wet and dry suits, portable air compressors, waterproof strobe lights, self-contained underwater cameras, mixed gas diving, deep submersibles, and habitats for extended water stays have made underwater photography easier, safer, and more effective. Remote-controlled devices take equipment to the depths required for ocean mapping, mineral exploration, and biological research.