After many years of diving and photographing marine life in tropical water around the world, I decided to explore the photographic potential that existed in cold temperate water, focusing my efforts mainly on the pristine coastal waters of British Columbia, Canada. Eventually, those efforts resulted in the publication of a book, Beneath Cold Seas: The Underwater Wilderness of the Pacific Northwest.
Very few books of underwater photography focus on cold/temperate ecosystems, and for good reason. The gear required for cold water diving is expensive and cumbersome, and the thick gloves required make manipulation of an underwater camera more difficult. Challenging diving conditions such as strong tidal currents and heavy seas are common. In addition, cold water usually contains many more particles of algae and other organic matter, often resulting in poor underwater visibility, making it more difficult than usual to obtain clear images with good color saturation. In an effort to obtain better quality scenic images and convey an unmistakable “sense of place” that would distinguish these cold water photographs from ones made in the tropics, I decided to include several “over/under” or “split” images, made with the camera partly submerged and partly above water. As you might imagine, composing and creating two distinct images with a single exposure while floating near the surface of a choppy sea can be challenging, both compositionally and technically.
For both images to be in focus, an extreme wide angle lens is necessary. Also required is an SLR camera in an underwater housing, equipped with a dome port 8 inches in diameter or greater. Wide angle lenses can only focus underwater when they are placed behind a dome port, and these ports create a “virtual” image that is often less than 12 inches in front of the dome. Because of this, many wide angle lenses require a supplementary +2 diopter when used in an underwater housing. And finally, for the lens to focus simultaneously on a close underwater “virtual” image and a distant above water one, a very small aperture must be used, usually in conjunction with an ISO of 800 or greater. Another obstacle to overcome is the difference in ambient light above and below the surface. Water absorbs light as it passes through to a much greater degree than does air, but even within inches of the surface the ambient light levels may be 2-3 stops lower. This occurs because most of the sunlight striking the surface of the water is reflected away, especially when the surface is choppy, or when the sun is relatively low in the sky. To compensate, a pair of strobes attached to the camera housing are often used to light the underwater subject.
Over/under shots are most easily accomplished while standing or kneeling in shallow water, and using a face mask or upward-angled viewfinder to carefully compose the double image; scuba equipment is not required, although a face mask and snorkel may be helpful. It is also possible to obtain split images in deeper water, and in this case, scuba gear is very helpful. While floating at or just under the surface, it is usually not possible to use the viewfinder effectively for split images. Instead, “grab shots” can be made while shoving the camera up and partly out of the water and depressing the shutter each time at what seems to be the right moment. The result of these exposures can be quickly checked on the back of a digital SLR and the procedure repeated until the desirable result is achieved. Note that if the exposure is made quickly, before individual drops of water can form on the outer surface of the dome, there will be little or no distortion of the above water portion of the image.
“Jellyfish in Browning Pass” was made in deep water while using scuba gear. The location is several miles east of Port Hardy, near the northern tip of Vancouver Island, British Columbia. Surfacing at the end of a dive, I found myself in the middle of a swarm of small cross jellyfish, with an occasional, larger moon jellyfish, and decided to attempt some over/under shots while waiting to be picked up by the dive tender. This photograph is one of about a dozen “over/under” images in my book Beneath Cold Seas: The Underwater Wilderness of the Pacific Northwest, published by the University of Washington Press (Seattle) and Greystone Books and the David Suzuki Foundation (Vancouver); visit www.beneathcoldseas.com for more information. – David Hall
Equipment and settings: Canon EOS 5D Mark II, Canon EF 17-40mm f/4L zoom lens in a Subal underwater housing with 8” dome port; a pair of Ikelite DS-125 substrobes was used to light the jellyfish. The exposure was set manually: 1/80th at f/22 – ISO 400; the lens was set at 17mm and the strobes at ½ power.