SAA Policies & Guides
Photography: Colouring in the Ocean.
In my previous article I describe how to get the most out of natural light shots. By concentrating on shade separation such as a dark subject against a light background you can produce stunning monochrome images such as silhouettes.
When taking this shot I was
unaware of the vibrant reds
of this scorpion fish. Only
when I looked at my film
back in the UK could I
appreciate
the coloured
captured by using flash.
But what most of us we want to capture is the natural colour of the marine world. For this you will need to use light from a flashgun, to paint back the colours lost underwater.
To record good sharp, colourful pictures your flashgun needs to be as close to your subject as possible. It’s important to appreciate that your flashgun has to be less than two meters from the subject so the flashlight will be able to overcome waters ability to absorb reds out of the shot. If you can’t get close then its better to think how the shot would look lit by natural light or as a silhouette then to try and then fail to light it with flash.
Flashgun basics.
The choice offered by manufactures of underwater flashguns could seem bewildering at first; they all however have a few things in common. The light output of a gun is described as a Guide Number (G.N.), the larger the number the more powerful the flash. If you know a flashguns G.N. your can calculate the correct aperture (f-stop) by dividing the G.N. by the subject distance. If this sounds complicated don’t worry; most flashguns can be set to automatic ‘through the lens’ (TTL) metering which allow the camera to control the flash output.
The flashgun’s beam angle, which is often measured in degrees, describes the amount of light coverage available to you. Using a custom made diffuser can spread out the light further, with the slight disadvantage that it reduces the guns G.N. so you will have to use a larger aperture.
Narrow beam flashguns are ideal for macro photography as they are general small and compact. For wide-angle photography the larger and more powerful the flashgun(s) are, the better. This will enable you to choose a smaller aperture to increase depth of field.
Macro subjects like this hermit crab
are fun to take as the flash freezes
the creature’s movement and records
it’s colour.
You should also take note of the number of flashes that a gun can do before having to replace or recharge its batteries. When a flashgun is fired it will take a few seconds for it to recharge this is called its ‘Recycling time’ and is important when take a series of photographs rapidly.
Some guns (generally the more expensive) have other features that can be useful. Not all shots lend themselves to TTL controlled flash so it is helpful to have a gun that allows you to shoot at half or even quarter power. A slave control means that the light from another gun can trigger the flashgun. This is useful when you need to position a flashgun off camera, as there is no lead. In previous articles I have discussed the value of a modelling light which shows you precisely were the light will fall. But, a word of warning; when choosing such a gun do ensure that the modelling light’s power source is separate from that of the gun or it will drain the power supply to the flash itself!
This large sleeping Hump head
parrotfish was shot on a night
dive in Sipadan using a 24mm lens
with a housed camera; the
flash
beam was wide enough to cover
the whole of the frame.
Check Film.
Whenever you acquire a new flashgun it’s a good idea to take a check film to verify the manufacturer’s recommended aperture/distance chart. This simply means that you take a series of photographs, (use slide film) with the camera and flash at set distances from your subject using a range of f-stops (apertures). Ask for the film to be developed but not mounted. This will allow you to select the exposure you like best for a set distance and aperture. Once you have done this compare it with the chart the manufacturer has given you and make any alterations necessary.
It is now becoming obvious that sessions to test your camera system are really important!
Flash only photographs.
Many underwater pictures rely solely on artificial light to illuminate them. With close-up photography you are trying to maximise the depth of field by using the largest aperture possible. This is determined by the power of your flashgun and its distance to the subject. The results of your test film will help you calculate the optimum exposure.
In the daytime this pipefish
would be difficult to photograph,
at night its colour was vibrant
Flash makes underwater close-up photography work as it brings back the lost colours. To make best use of these wonderful colours do take time to consider the composition of your picture. Those that are simple in design containing complimentary colours and with non-competing backgrounds seem to work best.
Night diving not only offers you an opportunity to photograph many creatures you wouldn’t generally see active in the daytime, but you’ll find some daytime creatures are more approachable at night when they’re dozy or asleep. Traditionally most photographers will opt to take close-ups at night, as most of the subjects are small. But don’t feel you have to limit yourself to macro work; it’s quite possible to use wide-angle lenses at night. As long as your flashgun beam covers the subject area then the resulting pictures will be well exposed, with any area not illuminated a startling jet black. So the next time you have the opportunity to do a night dive consider using a wide-angle lens and see the difference!
| First clicks | Shooting small 01 | Shooting small 02 | Getting the Big Picture |
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| Building Pictures | Lighting the underwater world | Colouring the Ocean | Balanced Light photography |
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