Underwater Photography Equipment

Professional Photography Service | Tips & Techniques | Equipment

Cameras & Film

In the early years of under water photography, medium format Hasselblad and Rolleiflex cameras (60mm square) were the preferred choice. These cameras however are large, and suffered from a lack of depth of field (about four times worse than 35mm cameras). As film emulsions improved, the field was taken by the small format (35mm frame) cameras. As under water photography is best in close-up, depth of field is very important. Resolution can be attained by using low speed film and longer exposure times or by resorting to negative film.

At the moment there are three basic options to consider: slide, negative or digital.

Transparencies, or E6 slides are the professional's choice for delivering pictures to printers and publishers. Their advantages are obvious: what you see is what you get. The slide is both the original and the finished product. It can be shown in a viewer or a projector. Each slide is packaged on its own, can be manipulated and stored on its own. Slides have good colour rendition and sharpness. They look like the printed image and the printing industry knows how to handle them and turn them into colour plates. But slides also have their down side. Because they are the unique and finished product, they can easily be damaged or lost. Printers often remove slides from their frames and greasy fingerprints, and miniature scratches are often left behind. Although good copies can be made of slides, printers often demand the originals. Slides fade when used regularly in projection, so only copies should be shown. Slides have high contrast, desirable to blacken the dark parts for projection. They show the world not exactly the way it is, with brighter colours, deeper shadows but the public has become accustomed to this, often demanding the postcard look rather than reality, particularly for advertising.

Because of its high contrast, exposing slide film correctly is rather critical. Even half an f-stop (25% light intensity) can spoil the result. To cope, photographers take many repeats of the same shot with varying exposure settings ('bracketing'). When an artificial light source is used such as a strobe, the number of repeats becomes very high, resulting in high wastage, costs and time.

For under water use, without practice and experience, results from slide film can be disappointing. Divers cannot reload films underwater and unfinished rolls are not kept for following dives, a new roll must be used for each dive. Realistically divers have only very few chances to shoot more than a few photos of the same subject in the same situation. Bracketing then becomes a hard liability.

Negative film. The colour saturation and sharpness of negative film has improved quite considerably in recent years (1990s). It is the favourite choice for amateurs but also for wedding photographers who often can not bracket their shots, or re-do them. Prints made from negative film can be handled without the risk of damaging the original. But negatives need to be left in strips of four to eight frames. So when a printer needs the original, he receives a strip of several frames. Printers dislike negative film because the result may change and there is no visual original to compare the printed image with, unless the corrected print is supplied as well. For a photographic library or stock clearing house, negatives are unacceptable because of this. But for the private photographer, shooting negative film gives the best value. Negative film is very tolerant to exposure, producing good results within a three f-stop tolerance. Negative film has low and linear contrast and portrays the world the way it is, much more so than slide film does. Prints can be enhanced by reprinting them lighter or darker. Negative film has very fine grain which allows one to use faster films. For nature photography under water, shooting negative film is very rewarding. Now that photographic images can be saved, filed and traded in electronic form, negative film has lost its earlier disadvantages and is rapidly becoming more popular for the professional photographer who wants quick, reliable and cost-effective results.

Digital cameras are now the favoured choice among amateur and some professional underwater photographers. Whereas progress in film emulsion technology has been slow, progress in electronic imaging has been rapid. Cameras now claim as many as 6 million pixels per image (a scanned 35mm Kodak Photo-CD image has 3000x2000 = 6 million pixels, compressed to some 6MB, about 80 lines per mm, the resolution of most slide films) Digital images show the result immediately, allowing for on-the-spot improvements to lighting, exposure and even contrast. Digital cameras are more sensitive, being able to take pictures in low light conditions. The CCD (Charge-Coupled Device) is small, allowing for short focal lenses with vastly superior depth of field characteristics. Very recent digital cameras now provide resolutions comparable to the 35mm frame.

For the amateur under water photographer who wants immediate results that can be reproduced professionally up to sizes of 100mm across, the digital camera is the solution. In the past few years digital video has stormed the world, providing superior pictures that can be obtained and printed easily. Fortunately, the high quality end of the digital cameras produce images with 10 or even 12 bits colour depth, thereby extending the range considerably (from 255 steps to 4096). But the JPEG compressed file format has only 8 bit precision.

Strobes

What is the ideal strobe for you? The strobe is an inseparable part of underwater photography and if you don’t already have one you’ll probably look to buy one as soon as you can. So what are the ideal strobe's characteristics?

Fast recharging: the faster the better, so you can make repetitive shots. 1-4 seconds
Small size and light weight: this is a compromise. Obviously a powerful strobe must have bigger batteries and a bigger capacitor and a bigger light bulb, so it comes in a bigger housing. Two small strobes enable you to use them for primary and fill in light sources and are easier to reposition.
Reliable and rugged: the strobe should always be more rugged than your camera.
Through-The-Lens exposure control: The camera controls the strobe. Very important for improving your success rate. Macro photography depends on it entirely. Take extreme care when mixing brands. A Nikon camera may not work well with a non-Nikon strobe. Modern cameras have very sophisticated flash strategies.
Inbuilt slave circuit: so that the strobe will trigger even though not connected to the camera. This enables you to take photos with two or more strobes, and the strobe can be held by the buddy or model.
Inbuilt exposure control ‘zoom’: when used on its own in slave mode, the strobe must be able to control its own output depending on the amount of light returned from the subject. Camera and remote strobe must agree on film speed and aperture setting.
At least guide number 30 or 60: the guide number is standardised at a film speed of 100 ASA and distance in metres. Thus GN 30 means f11 at 3m, f16 at 2m, f32 at 1m. Note however that guide numbers are often slightly exaggerated.
Inbuilt search light: An inbuilt search light can often be placed central to the round flash tube, giving precise direction. However, this light runs from the strobe batteries and may consume most of their energy. Make sure this light is of the latest type, preferably with thrifty LED bulbs.
Wide angle or Macro: if you have a wide angle lens, you must have a wide angle strobe. Be suspicious of diffusers because these do not produce even lighting. For macro photography you will need a smaller strobe so consider which strobe is suitable.
Plug and unplug in the water: in the old days it was possible to plug and unplug strobes in the water because the camera presented only a make-contact without voltages. Present-day strobes, however, present a number of signals to and from the strobe, often at high voltages and impedance. A single droplet of salt water can now seriously upset the reliability of your strobe. It is not a desirable situation, though.

Professional Photography Service | Tips & Techniques | Equipment