Divernet

There are almost 11,000 known shipwreck sites around the British Isles. Many of these are on the deep side. Such wrecks impose so many diving problems, including physically altering and balancing partial pressures of gas mixtures, that you sometimes feel youre not supposed to be there!
Add in all the extra equipment needed, acquisition of knowledge, the journey out to the site and getting the slack right, and Nature may have a point. Throw a camera into the equation and you find yourself questioning your own sanity.
Basic underwater photography presents its own problems, but the deeper you go, the more technical problems begin to build.
Filtration of light through water affects colour according to depth. Take a millpond day with the sun high. The first colours to be lost are reds and oranges at about 8m, then yellows and greens at around 20m and finally blue.
To keep those precious colours, you have to take your own cans of light in the form of flashguns.
Beyond 30m you need some pretty big mothers to illuminate large sections of wreck, especially if you want to bring out colour as well. But artificial lighting also tends to illuminate suspended particles and cause backscatter, a problem that haunts British photographers.
Colour and light - two significant problems to overcome. But instead of battling against the odds, why not simply take them both out of the equation By accepting that depth robs us of colour, and shooting with monochrome film, you can not only shed an element of stress but change the entire mood of a typical British shipwreck scene.
Professional land photographers regard monochrome work as having a certain integrity, so why should this not also be the case under water
I found that capturing large sections of wreck on film meant backing off some distance to fill the lens. Even with a large guide-number, flash was not powerful enough to illuminate the scene. So I felt that natural light and long-exposure photography was the way forward.
The world of ultra-fast films and a new concept of exposure now followed me like a black cloud. The biggest question: would British diving conditions open a window and let me try these techniques out
Most of the deep wrecks I photograph, especially in the English Channel, lie in utter darkness. But on odd occasions a friend or skipper telephones with news of brilliant visibility, which in turn means clean waters. If a mid-day dive with the sun at its highest is possible, the available light window is suddenly open.
To photograph big sections or entire wrecks, the wider-angle the lens the better. We are also looking for some serious depth of field in order to capture the distance, which means small apertures down to f22. But small apertures with low light levels also mean longer shutter speeds, and the final link in this nasty little chain is picture blur caused by movement and camera shake.
The answer was a tripod, even though introducing such a device to the deep wreck-diving community was inviting a hearty laugh at my expense.
Ultra-long exposure photography can be practised only with housed SLR systems, because slow shutter-speeds are limited to 1/30th of a second with Sea & Sea and Nikonos cameras.
Using a Nikon F90x in an Aquatica housing, all I had to do was design an adaptor that would easily slot into a tripod shoe.
Fortunately, a former Diver Photographer of the Year, Ken Sullivan, lives just round the corner, and Ken has been responsible for system modifications to the equipment of many leading photographers. Some simple machining and the job was done. With my camera attached to a heavy-duty Velbon video tripod, I was ready to shoot.
A chance to return to Ireland for a few weeks was too good to turn down. All I had to do was work as hard as I could alongside the crew aboard the expedition vessel Loyal Watcher.
In return for my efforts, I would be able to dive some of the most fabulous wrecks in the world while testing the tripod approach.
I would be diving on a rebreather, so the depths at which I was shooting would pose no significant problems, and I could concentrate on creating images. I had all the time in the world!
My choice of film was considerably narrowed by the fact that I wanted slide format for presentations.
Monochrome slide film is on the rare side, but some research showed Agfa Scala 200x to be as good a choice as any. Its a professional variable-speed film that can be pushed or pulled between 100 and 1600 ISO.
I had also discussed film with US shipwreck author and photographer Brad Sheard. He strongly recommends Kodak Tmax, a fast 3200-speed mono print film normally used without a tripod. Its ultra-fast speed would allow handheld use at around 1/30th sec.
In trying to capture deep-wreck images anything is worth a try, but I have yet to experiment with this option.
The key to this type of photography is almost certainly composition.
Previous exploration of a site and awareness of exactly which image you intend to capture before entering the water can make all the difference.
Not all subjects are suitable for ambient-light photography, but big wrecks, as well as subjects close to the surface and subjects of high contrast, are the best options. Avoid anything that does not stand out against a background.
Calculating exposure variations, even deciding which part of the scene to meter, is probably the hardest task. So many variables affect light levels at depth that without considerable experience you cannot estimate accurately the amount of light reaching your subject.
Acknowledging the problem, many cameras have built-in light meters and can automatically measure levels and adjust camera settings accordingly.
Bear in mind that meters average the value of all light they see. Based on that average, they suggest settings (f-stop/ shutter-speed combinations), all of which result in the same exposure.
Overcome uncertainty about exposure-metering by bracketing. Shoot several frames at slightly different settings, and single out the best image on later development.
The first of a set of frames would be shot using aperture-priority, a function of SLR systems that gives ideal control over depth of field.
After deciding the aperture required, the cameras micro-computer automatically selects a corresponding shutter- speed to give what it believes to be the correct exposure.
I was searching for detailed images with great depth of field, so this seemed an appropriate way to start a bracketing set and gave early indications of an average exposure under the conditions on the day. After three frames ranging from f11to f22, the systems controls were switched to manual. The electronic viewfinder display could be used to determine the exposures.
Once again, a small aperture was selected, though this time the shutter-speed was also adjusted until it corresponded with what was deemed the perfect exposure.
In theory, the long exposure determined would be exactly what the cameras computer requested in aperture-priority mode.
Results showed that the exposures in both modes were exceptional, and exactly what I was looking for.
Adjusting the shutter-speed by one or two exposure values either way over-rode what the micro-computer wanted. The resulting over- or under-exposed shots often produced interesting silhouette effects, depending on conditions and camera angle.
All the metering undertaken with the long exposures was done in conjunction with the field-proven 3D matrix system, which was obtained through an eight-segment sensor and the AF Nikkor lens itself.
The system takes into consideration scene contrast, scene brightness and subject-to-camera distance.
The result in this situation was an optimum exposure for each frame, even in the complex lighting situations I was throwing at the camera.
If after my dive I had frames left on the roll, I would switch once again to aperture-priority on the ascent and look out for the possibility of silhouette images of my colleagues decompressing. Again, a variation of apertures gave interesting effects against the sun using monochrome film.
Aperture-priority was the easiest to shoot in this situation, given the effort involved in continuously rotating the speed dial while monitoring buoyancy, as the shutter-speed often rose well above 1000th of a second.
At the depths at which I was shooting, the micro-computer asked for exposures ranging from 4sec to a whopping 25sec. The latter granted me enough time to relax behind the tripod and monitor my rebreathers computer for a change.
The long exposures were problematic only when I was working with a diver to provide scale within the scene, because fin movement was as inevitable as trailing light beams, but divers were angels compared to the fish!
I found that acting like a screaming break-dancer behind the tripod often prevented fish entering the field of view during an exposure.
The only drawback was that, as I was using a closed-circuit rebreather, there was always a chance that a passing colleague might mistake me for someone having a convulsion!
Large shoals of fish that refused to budge from a scene resulted either in an interestingly busy image or simply one for the bin.
Whether my images produced using these methods are acceptable to the experts is debatable, but interest in them has been overwhelming, because they do allow everyone to see deep shipwrecks as I see them.


Bow
Bow of the Justicia, manual exposure-metering with Agfa Scala 200x slide film pushed to 1600 ISO, exposure f16-10sec minus one exposure value
Sherman
Sherman tanks on the Empire Heritage. The smallest aperture possible captured the depth of field, and the 10sec exposure has blurred the fish
even
even at 69m a high sun has given enough light to freeze the fish beside the prop, f11-2sec Agfa pushed to 1600 ISO
tripod
tripod erected atop wreckage to capture deck winch and background mast. Other than one static fish the shoal was on the move during a 5sec exposure in aperture-priority pushed to 1600 ISO
The
The tripod has been angled towards the light source on the seabed to capture the boilers on the Empire Heritage, manual exposure of f11 for 3sec with Agfa film pushed to 400 ISO
remaining
remaining film after a dive can be used to capture effective mono images of divers decompressing. Here aperture-priority was chosen over manual for fast results to avoid buoyancy problems, using f16 at 1000th sec

  • Visit Leigh Bishops image-based website at www.deepimage.co.uk