Since the development of the Aqualung by Jacques Cousteau and Emil Gagnan in 1943, we have been able to stay underwater safely and comfortably for extended periods of time. This amazing technological breakthrough allows us to discover, explore, and photograph the wonders of the underwater world. It was one of the first challenges underwater pioneers, such as Cousteau, faced was capturing the beauty and mystique of this foreign world on film in order to share it with those unable to see it for themselves. This challenge has been answered over the past fifty years, in both still and motion pictures. Today, television and cable audiences can frequently find a documentary or special about an aspect of the underwater world.
What makes the underwater world so intriguing and appealing to photographers? First, it truly is another world - a world of motion and tranquillity. Like outer space, it offers photographers a sense of adventure, the thrill of discovery, and the promise of excitement. The underwater world also appeals to photographers because its natural state seems so foreign to ours. In part, this reflects tremendous differences between terrestrial and aquatic ecosystems. Land environments are dominated by plant life, while the underwater environments are dominated by animal species. When we describe land environments, we refer to grasslands, redwood forests, and oak tree groves. When we describe underwater environments, we refer to coral reefs, oyster flats, and mussel beds. In addition, the animals photographers encounter underwater often have unusual, if not bizarre, shapes and colors that provide a never-ending supply of photographic subjects.
Land objects, which take on an entirely different nature and sometimes increase in value when submerged, can be excellent "foreign" underwater photography objects. Objects such as doorknobs, old nails, and bottles are usually termed junk, but they are considered treasures after resting at the bottom of a body of water for a decade or two. The broken hull of a lifeless ship sixty feet below the surface is another intriguing photo opportunity that lures many photographers into the water.
Although the fundamentals of land photography - like measuring light, calculating exposure, focusing, framing, and composing - are essentially the same fundamentals applied in underwater photography, the challenge of capturing images on film underwater lies in dealing with the constraints of the underwater environment. First the photographer has to master the skill of scuba diving. Mastering this exhilarating sport is essential to mastering underwater photography. The aquatic realm imposes some unusual environmental constraints on both camera and diver alike. The relatively poor clarity of water as a medium in which to photograph, and the loss of and change in the quality of available light underwater are the most serious constraints.
Environmental constraints also require photographers to develop and sharpen their organizational and planning skills, which make or break any attempt at underwater photography. The steps it takes in order to simply get to the subject are often complex, involving events beyond anyone's control. For example, when an electronic flash fails underwater, a photographer cannot simply reach into their equipment case and pull out another one. Replacing the flash unit requires them to alert their diving companion, get back on the boat, take off most of the gear it originally took them a half an hour to put on, find a dry place to work on the equipment, and the get back in the water. Being unable to change film underwater is the best example of a photographic environmental constraint that requires careful planning. On land, photographers usually take this simple procedure for granted, but it is a significant part of preparations for an underwater shoot.
On the recreational level, the availability of underwater photography equipment at an affordable price allows sport divers to capture underwater encounters on film. More and more divers are putting down spearguns and picking up cameras. On the professional level, the quality of underwater images continues to improve as increasingly advanced camera systems become available and as the market for such images broadens. The growing public awareness of the condition of the oceans - through the efforts of such conservation groups as Greenpeace, the Cousteau Society, and the World Wildlife Fund - continues to require high-impact, high-quality images that reveal the delicate nature and the precarious balance of the underwater world. At any level, underwater photography is just as exhilarating to look at, as it is to photograph it.
The two words that characterize all underwater photo equipment are "waterproof" and "rugged." The primary consideration in designing any piece of underwater photo gear is keeping the internal parts dry. This requirement shapes the design process for developing submersible camera systems. It calls for the use of strong, corrosion-resistant materials, as well as testing facilities that allow manufacturers to experiment with units under varying pressures. Camera equipment for underwater photography must also be able to withstand extended periods of exposure to vibrations, the corrosion that saltwater can cause, violent knocks and bumps, and a variety of other abuses that would destroy even the most durable land camera immediately. As a result, most underwater camera equipment is heavy, bulky, oversized, and awkward to handle, at least on land.
Camera systems were developed along two major lines. The first consists of taking an existing land camera and designing a watertight vessel called a housing for it. Not only must this system accommodate getting the camera in and out of the housing in order for photographers to load the film and change lenses, but it also must have through-vessel fittings so that they can manipulate the camera controls from outside it. However, each fitting is a point on the housing where water can seep in, and each requires a seal. Early housings were not too reliable. Today's models are made of both molded plastic and metal, and are extremely reliable if maintained properly.
In the second approach, the camera is the housing: the camera body represents the vessel with the outside controls that are directly linked to the inner workings of the camera. These controls include the shutter-release button, the lens-aperture control, and the film- advance lever. This approach is applied to viewfinder cameras only, with which it works quite well. The degree of complexity in the workings of single-lens-reflex cameras has, for the time being, prevented this approach from being used with these cameras.
Lens selection for underwater photography is rather limited, mainly because of the need to shoot at small camera-to-subject distances. Because there is no room for long distance photography underwater, telephoto lenses are not needed. Zoom lenses are also rarely used underwater because they require an additional housing. Most underwater photography is done with either close-up or wide-angle lenses, both of which allows photographers to get close to their subject.
Because of the general lack of ambient light below the water's surface, most underwater photography requires supplementary light as either fill or, more often than not, key lighting. Additional light is usually needed to show the true colors of all of the subjects. These are usually lost because of water's differential absorption of visible light. There are three sources of artificial light for underwater use: movie lights, flashbulbs, and electronic flash units. Movie Lights - This source of artificial light allows photographers to dim the light and see in advance exactly what the picture will look like. However, movie lights designed for underwater photography are not appropriate for still photography, primarily because they require large quantities of power in order to produce enough light to adequately cover most picture areas. Another problem: the color temperature of most movie lights does not match the color temperature ratings of most still-format films. Flashbulbs - These artificial-light sources enable photographers to use cameras that synchronize flash firing with fast shutter speeds. Underwater photography subjects rarely have to be photographed with a flash at shutter speeds greater than 1/90 of a second because of the density of water: it significantly slows down almost any object moving through it. The main problem with flashbulbs underwater is getting a dependable one to make contact with the flash socket in water. Electronic Flash Units - Essentially, all artificial light for underwater photography is supplied by electronic flash units. The advantages of using them include dependable firing and synchronization, adequate light output and area coverage, color temperatures that match existing film types, and adaptability to automatic light sensing/output or manual modes. There are a variety of makes and models to choose from in this line of artificial light.
For the most part, all underwater photography is done in the 35mm format. Using medium-format camera systems underwater is complicated because of the difficulty in designing and constructing waterproof housings for them. Another reason for the dominance of the 35mm format in underwater photography was the development of the Nikon's 35mm format system. Its widespread popularity in both the consumer and professional markets has had a big influence on the technological research, design, and construction of underwater camera equipment. While the size of the consumer market for underwater camera equipment is growing, it is still quite small in comparison to the market for cameras used on land. As a result, the research and development of underwater gear are slow.
Within the 35mm format, both light sensitivity and color characteristics determine film selection for underwater photography. Although print film gives photographers more leeway in regard to exposure during the developing process - which can be particularly helpful in underwater use where measuring ambient light is often difficult - slide film seems to be preferred for two reasons. First, it is less expensive than print film. Given the amount of film photographers go through underwater, price can become an important consideration from a budgetary point of view. Second, if the images will be used commercially, transparencies are generally preferred: they tend to reproduce better.
In addition, black and white film is used very little underwater; getting good shade contrast is difficult in most underwater situations. Because of this, black and white images usually appear dull and extremely monochromatic; they lean toward a fairly even gray tone, and everything in the picture blends in with everything else.
With the limited levels of ambient light underwater, "fast" color films are generally more useful for images in which ambient light is key. Some photographers use films with ratings of ISO 100 and higher despite the inherent problems of graininess and loss of resolution with the faster films. These include films with ISO ratings of 200 and 400, whose grain quality has been improved recently. With ambient light, images will lean heavily toward a monochromatic combination of blue and green - a result of water's color-absorption properties. With color-print film, warm colors can be enhanced to a certain degree during the printing process. This can also be done with slide film if an internegative is made and a print is produced from it.
Getting sharp, clear images underwater is hindered by several factors that vary with the type of camera system being used. With viewfinder cameras, the first concern is accurately estimating camera-to-subject distances. Refraction of light plays a role here: it confuses the issue on a conceptual level. As a result of refraction, the subject appears to be approximately 25 percent closer than it actually is. And, because there is another air/water interface between the camera lens and the surrounding water, the camera also "sees" the subject as being 25 percent closer than it is. So at whatever distance photographers estimate the subject is from the camera, that is the correct focus setting for the lens.
Focusing single-lens-reflex cameras underwater has its own set of difficulties. The main problems are being able to see through the viewfinder and getting a clear image on the focusing screen. Basically, photographers are looking through five glass interfaces: the face mask, the viewing window in the waterproof camera housing, the viewfinder of the camera in the housing, the lens, and finally the window on the other side of the housing through which the lens sees the subject. The generally low levels of light underwater further complicate these problems.
All information gathered from various Internet sources and Underwater Photography by Charles Seaborn published by Amphoto, New York, New York. 1988.