SAA Policies & Guides
Photography: Balanced Light photography.
In my last two articles I have described how to light shots solely by using sunlight or flash. But by combining the two techniques a very natural looking photograph can be obtained which everyone can identify with. Named balanced light shots, these pictures consist of a background lit by sunlight and a foreground illuminated by artificial light to restore the colours lost by water absorption.
Balanced Light Techniques.
Close-up shots with natural
coloured backgrounds are
possible if you follow
the advice given in this
article. The red soft coral
contrasts well with blue
sea as is shown here.
The starting point for all balanced light shots is an ambient light reading. First decide in which direction your camera is going to point, into or away from the sun, towards the surface or into open water. Once you have chosen your camera angle note the exposure. This reading will consist of a set aperture for a given shutter speed. If you are happy with the colour of the background as seen through your viewfinder, simply accept the light reading. If not you can lighten or darken it by either slightly over or under exposing the shot. I often take a few shots varying the background light exposure (this is called bracketing) and then select the photograph I like the best. It is important to remember that there is no one single correct exposure but a whole range of acceptable ones.
The light reading you have chosen for the background will have a set aperture for a given shutter speed. The aperture governs the distance you have to hold your flashgun from the foreground subject as well as the picture’s depth of field. If your shot requires a large depth of field then you will be looking for an aperture setting of f11 or higher. At these small apertures you will be selecting slower shutter speeds.
Wide Angle balanced light shots.
This UK shot shows that
you can use balanced
light techniques in our
darker waters.
To use an example, at mid-day in tropical waters a light reading taken horizontally of the water column at 10m (with 100ASA film) would generally give a reading of f8 at 1/60s. At this aperture with a wide-angle lens and medium powered flashgun a foreground subject about a meter away will be well lit and a balanced shot produced. If the subject was just 30cm away from the camera and flashgun though, it could well be overexposed since a TTL flashgun might not be able to quench its flash fast enough. At f8 the depth of field would probably not be great enough to have both the foreground and background in focus. Some of these problems could be overcome; you could move the flashgun further away from the subject, or fire it at say ¼ power if that were possible. But nonetheless you would be left with a poor depth of field.
My flash has ‘painted in’
the
colour of the fish
and
soft coral, but is
not
powerful enough to
illuminate the diver,
who
is silhouette against
a
balanced blue sea
background.
By increasing the aperture (f-stop) you would be able to reduce the flash to subject distance and increase the depth of field, but you’d also darken the background. I would advise you to take a shot at this new setting then reset the shutter to a slower speed to lighten the background. From these bracketed shots select those you like.
Close-up balanced light shots.
I often show close-up shots that have a dark or black background; most underwater photographers have plenty of these shots. The problem with them is that lacking a blue background, they don’t look natural. When shooting close-ups we use as large an f-stop as possible and a shutter speed as fast as the camera-flash synch. will allow. This gives us sharp pictures with a good depth of field but un-natural background. To overcome this artificial look you could use larger f-stops to allow more background light in. The problem with doing this is that you reduce your depth of field and have to hold your flashgun further away from the subject. A better technique, and the one I would recommend, is to reduce the shutter speed whilst maintaining a small aperture. Select a subject that is framed against open water then whilst focusing on it reduce the shutter speed until a ‘correct exposure’ reading is obtained. For example this could be ¼ second at f32. As the flash duration is only about a thousandth of a second, camera shake is not a problem and the main subject should be frozen, sharp and correctly exposed. The image’s background, which being colour need not be sharp, will be added by the long exposure.
This slow moving Lion Fish
has allowed me to capture it
against a natural looking
background of blue water.
One Flashgun or Two?
This is a question I’m often asked. I would advise everyone who is starting to take underwater photographs to use only one flashgun. If you are a beginner and are unhappy with the lighting then experiment with different lighting angles before considering adding a second light. Most of the shots I have used in my Photo Clinic articles were taken with just one gun.
It has only been in the last couple of years that I have used two flashguns on a regular basis. I use a second flashgun when taking close-up photographs to reduce the harsh shadowing caused by only one light. With some of my wide-angle shots a second light helps give a more balanced lighting and increases the area of flash coverage. If you are tempted to use a second flash try and borrow one first before splashing out.
This slow moving Lion Fish
has allowed me to capture it
against a natural looking
background of blue water.
To conclude, although much that I have written above may seem daunting, give it a try. If the background can be lit by sunlight your flash will add colour to the foreground subject producing a pleasing and natural shot. Just take notes of what you do and experiment; this is the best way to learn balanced light photography.
| 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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