Underwater photography is one of the most challenging activities you can add to diving. Not only must you control your buoyancy and life support in an alien environment, but you have to master the technicalities of producing a successful picture.
Thats why many beginners start by concentrating on macro photography. The techniques and variables are more controlled, so the chances of producing more pleasing images are better.
However, macro should not be forgotten as you gain experience. It is often the only option when diving in our home waters, where stunning visibility is the exception, not the rule. And although the techniques appear simple, it can be difficult to achieve repeatably good results within the limitations of your equipment and the prevailing conditions.
The term macro refers to the reproduction or magnification ratio of the final image. This is generally accepted to be in the range of 1:4 (quarter life-size on the film) to 1:1 or 2:1 (life-size and twice life-size on the film). It is possible to gain higher magnifications in the range of 2:1 to 5:1 and this super macro range is becoming increasingly popular with underwater photographers seeking new challenges.
Owners of Sea & Sea cameras have a choice of supplementary close-up lenses complete with framers in the range of 1:4 to 1:2. These clip to the front of the fixed 35mm lens and can be fitted and removed under water, which is handy if a larger subject turns up.
For Nikonos owners its best to use extension tubes. These fit between the camera body and the lens and come in the 1:4 to 2:1 range, from various manufacturers. As they form part of the watertight camera system, they cannot be removed under water, so you are committed to your chosen reproduction ratio throughout that dive.
Photographers who use housed cameras perhaps have the greatest flexibility. The macro lenses available can focus from infinity down to 1:2 or 1:1, so a range of subject sizes can be covered on one dive. They are available in focal lengths of 50/60mm, 90-105mm and 180-200mm, the differences being the stand-off distance from the subject at maximum magnification and the picture area covered at the infinity setting.
Longer focal lengths have narrower angles of view and a greater stand-off at minimum focus.
You will need to illuminate your photographs with flash. The best are perhaps the smaller guns, or even exotic solutions such as ring-flash, but if you have only one larger, all-purpose flashgun, this will do the job.
TTL flashguns work well with macro, as the subject generally fills the frame and has even contrast. However, it is not difficult to use a manual flashgun, particularly with the Nikonos and Sea & Sea systems, which have a fixed distance to the subject.
Experimentation will soon reveal the ideal apertures for your gun. You will want to select the smaller apertures (f16, f22, f32, for example) to maximise the depth of field in your picture. No matter which macro system you choose, the depth of field is extremely small, often less than 12mm, so focusing is critical.
At first you might consider the amphibious camera with the framer to be the easy option. Put the subject in the framer and bingo! This often works, too, but grasp some basic rules and you can make it work every time. The point of focus is right between the posts of the framer, so if your subject projects forwards through them or is behind this plane and on the edge of the depth of field, it will not be sharp. Get used to looking closely at the subjects position in the framer before taking the shot.
Also remember that the framer is bigger than the picture area - if it wasnt, it would appear in the picture! So place your subject well inside the framer or you will cut off the edges in the final image. Only experimentation will reveal the nuances of your own framer.
Using a housing is perhaps a little easier. You can see what is in the picture through the viewfinder and tell if it is sharp. Auto-focus is a great help here, as many systems will not release the shutter unless the image is in focus, but it is also more difficult to hold the larger system steady at high magnification when the depth of field is so small.
Your camera system needs to be as neutrally buoyant as possible. If yours is heavy, consider adding a small float to trim it. You also need to perfect your buoyancy control, or perhaps start with subjects close to a sandy patch so that you can steady yourself to focus.
Forget the usual rules of using flash under water. For general stand-off or wide-angle photography we are most concerned about backscatter caused by illuminating suspended particles in the water. You would avoid this by lighting the subject from above, at an oblique angle of, say, 45, so that any reflection goes back towards the flashgun rather than the lens.
In macro photography you are generally so close to the subject that if you try to light from a distance at 45, you risk missing the subject or casting a shadow over it, and perhaps under-exposing with the small aperture selected. Your flash could be too far off.
With the subject close to the camera and the angle of view of the lens extremely narrow at high magnification, you can ignore backscatter in all but the most turbid conditions.
Have your guns close to both camera and subject to ensure that there is sufficient light for the exposure, and that it is falling on the subject. Short flash arms are best for these techniques, or consider mounting your flash on top of the camera or on your housing port.
Hotshoe flash mounts are available for both Sea & Sea and Nikonos cameras, and there are several bracket options available for mounting one or more flashguns for your housing port system. These are best suited to small macro flashguns, so if you have a larger gun or cant find what you want, consider modifying an existing arm or make a bracket to suit.
Using these close lighting techniques can create strong and sometimes unwanted effects. If you have only one flashgun, top-lighting is probably best, as strong side-lighting can cast unattractive black shadows to one side of your subject. These can be eliminated or softened by adding a second flashgun of equal or lower power, or a white reflective plastic panel to reflect light and fill the shadows.
You can also try flat-lighting - aiming the gun directly at the subject near the camera or port. This can have the effect of casting the shadow directly behind the subject, where it is often hidden.
Ring-flash uses this technique and is becoming more popular with those photographers who use housed systems and longer macro lenses.
Another feature of which to beware when using a framer system is that strong side-lighting can cast a shadow from the framer onto your subject. Remove one frame post to avoid this.
Some manufacturers have designed their posts to be screwed in or out, but with other makes you will have to cut a post off or make up a separate one.
Now you can start thinking more creatively about the position of your subjects and how to portray them. Negative space, the area behind and around a subject, needs to complement or contrast with it to stand out.
Look for subjects with a strong colour or textural contrast with their backgrounds, or for those in which the background is distant and will appear blurred, or be far enough away to be underexposed and appear dark.
Alternatively, select subjects which have open water behind them. This will appear black in the exposed image, contrasting well with brightly coloured subjects you might choose, such as anemones and nudibranchs.
Consider trying to enhance the background through back-lighting, using either natural available light or artificial strobe light.
To use natural light you need to balance the flash exposure with the available light. This can be achieved either by using a wide aperture and reducing the depth of field dramatically, or by using a long shutter speed to record some of the natural light.
Nikonos and Sea & Sea users can attempt this by picking subjects which allow you to position the camera so that it points directly toward the surface and perhaps the sun.
Because the slow shutter speeds available are limited with these systems, you need to use a wide aperture and be very cautious in positioning the subject within the framer to ensure that it is in focus.
If using a housed camera system, the technique is easier. Modern auto-focus cameras offer slow flash synchronisation speeds and rear curtain synch which, combined with small apertures, will produce a balanced light picture with good depth of field.
However, you will still need to seek out subjects which allow a low angle of approach to include as much of the surface light as possible.
The third option is to use a second or third flashgun to provide back-lighting. This can be a slave gun fired by the main strobe or a TTL strobe fired by the camera. Whichever method you choose, you will need to experiment with the position and distance of the flash from the subject to get the exposure correct. Because the flash is firing towards the lens, it is very easy to overexpose.
You can vary the effect of back-lighting by adding coloured filters, perhaps green to simulate temperate waters, blue for tropical and a variety of others for special effects.
If life-size reproduction is not enough for you, try super-macro in the 2:1-4:1 or even 5:1 range. You need to be using a housed macro system with one of the longer lenses - 90/105mm or 180/200mm - to maximise the working space between camera and subject.
To increase the magnification, you have three options. The first is to add one or more close-up diopters to the front of your lens. These are generally land diopters in the range of +2 to +6 fitted to the lens inside the port, although wet diopters which fit to the outside of the port to produce a 2:1 image are available from Nexus and Inon.
You could add extension tubes between camera body and lens. These come in various sizes for differing levels of magnification, but to install them you will need an extended port or extension ring to accommodate the extra length.
You also need to adapt aperture gears and focus gears to fit if your housing manufacturer does not supply them.
The other option is to add a tele-extender or tele-converter to your lens. These are generally available as 1.4x, 2x and 3x, with matching increases in magnification. As with extension tubes, you need the port and gears to match this equipment.
And to move into the 3:1 to 5:1 range you will need to use a combination of the above.
As you extend the light path to the film, light is lost. This affects the usable apertures on the lens and reduces image brightness in the viewfinder. Using TTL flash will automatically compensate for this effect.
The other downside for auto-focus cameras is that the camera finds it very difficult to lock onto the subject. It is often better to resort to manual focus.
A bright focus light can be used to help the auto-focus lock on. The process can be difficult and frustrating at first, but perseverance should eventually produce some stunning results.
Whatever the subject you select, in the UK or overseas, try to imagine the finished image in your mind and concentrate on seeking out rich, contrasting colours. Using a small torch and even a magnifying glass can help in your search for the ideal subject and will keep you happy for dive after dive - even when the viz is not perfect.
1 Housing a modern autofocus SLR camera with a macro lens is perhaps the most flexible equipment choice
2 The Nikonos requires extension arms for macro photography
3 Macro lenses for an SLR camera come in three focal lengths
4 Mounting a flash on top of the camera is effective for macro work
5 An alternative to twin flashguns is a simple white plastic reflector to fill shadows
6 One option for greater magnification is a 2x converter, but an extension ring or longer port is needed for the additional length
and 7 Wet diopters or close-up lenses are an easy way to boost magnification to 2
Jewel anemones in the UK, a classic extension-tube subject shot at 1:1
juvenile soft coral in the Red Sea - use a small aperture and fast shutter speed to create a dark background and boost contrast
look at bigger subjects such as this clam siphon to reveal striking details and patterns
Leather coral polyps in the Red Sea - introducing back-lighting allows you to vary the appearance of macro shots