A few great shots to whet your appetite before we get started...
Above: Grey Reef Shark in Bora Bora by D. Lloyd - Camera model Sony Cybershot Exposure time 1/560 sec F-number f/4 ISO speed rating 100 Date 2002 Lens focal length 13.6 mm
Above: Marine sponge by D. Lloyd using a digital camera at a depth of approximately 100 feet in the Cayman Islands - SONY CYBERSHOT Exposure time 1/60 sec F-number f/2.8 ISO speed rating 100 Date 12 June 2002 Lens focal length 8 mm
Above: Eritrean butterflyfish. Underwater photograph, Sharm el Sheik, Egypt, Red Sea by CC-BY-SA-3.0-2.5-2.0-1.0], Bernard E. Picton Chaetodon paucifasciatus Nikon F3, Aquatica housing Lens 60 mm macro Focal length 60 mm
Getting the right underwater digital photography camera settings is not so difficult and once mastered you will have the power to conquer one of the most fascinating of all forms of photography. However, there are some definite differences in the way light is handled by a camera but if you bear a few things in mind you will find that you can take great shots without having to buy expensive equipment.
The main problem photographers face with underwater digital photography is that water is not transparent like air, and sand, dust and other particles in the water absorb the longer wavelengths of light.
This results in a loss of colour and contrast when you get to any significant depth and everything appears bluish-green.
This can be compensated for quite simply by altering the white balance setting: use daylight mode up to about 10 meters, cloudy mode beyond 10 metres or when macro shots look a little bluish.
Another good technique is to use fill-flash which will provide full-spectrum light.
Sea Horse Photographed at Arraial do Cabo, Brazil: (Photo: Laszlo Ilyes)
Snorkeling with Jellyfish: 1/50 sec, f/3.5, ISO 80, focal length 6.6 mm (Photo: Tata Aka T)
Another potential problem with digital photography underwater is that beneath the surface of the water light diminishes the deeper you go.
Some subjects further away from the camera will also look colourless and indistinct an effect which occurs even when the water seems to be clear.
The use of an external flash becomes necessary in this case but if you take shots close to you will find that the on-camera flash works well. 12 inches away from your subject is good. If your camera has a setting for forced-flash it would be good to use it.
Also, if using a wide angle lens under water, the camera must be positioned further away than you would with the same focal length on land in order to get a similar outcome.
This is because of the optical illusion underwater that objects appear larger and closer than they really are. Check the manual before you set out so you know what the minimum focusing distance is.
Penpoint Gunnel Photographed at Three Tree near Seattle: ISO 100, f/4.4, 1/70 sec, focal length 15.3 mm (Photo: Jeanne Luce)
Underwater Digital Photography Camera Settings 1
Shutter speed is how long the camera allows light to reach the image sensor. Shutter speed is expressed in fractions of a second (for example: 1/250th of a second). The faster the shutter speed, the less light reaches the image sensor. Slow shutter speeds allow more light to reach the image sensor but there is an issue of holding the camera steady enough for a sharp image.
So for underwater shots when you are photographing fast moving objects like fish you should set your camera to shutter priority, then choose a fast shutter speed and let the camera adjust the aperture accordingly.
Underwater Digital Photography Camera Settings 2
If you are shooting objects close to, you might prefer to set your camera to aperture priority. Since aperture influences the depth-of-field, or the range in which things are in focus, a smaller aperture (higher f-stop number) will give you more of the image in focus.
The opposite is also true - the bigger the aperture (smaller f-stop number) will give you less of the image in focus. Simply put, if you want to shoot up close and lose the background, use a smaller f-stop number and everything behind your subject should be a nice blur.
Underwater Digital Photography Camera Settings 3
The ISO you choose should be as small as possible. Although it is tempting to select a high ISO to compensate for the lower light level underwater, high ISOs give much more digital noise, particularly apparent in less expensive cameras. So use the lowest possible setting you can as the grainy effect of digital noise works well with journalistic shots but not so well with nature shots. ISO 100 is a good default setting to start out with.
Underwater Digital Photography Camera Settings 4
Bracket your shots if possible. This means taking the exact same photo at three or more varying settings: the second and third shot will be over-exposed and under-exposed slightly, compared with the first shot. Some cameras have a setting which lets you bracket automatically - read your manual to see if it's possible to do. It's well worth a try.
Underwater Digital Photography Camera Settings 5
You can adjust the levels in Photoshop afterwards if you find the contrast of an image is too low, as can sometimes happen with underwater photography. Check the histogram - a flat image will have the histogram centred towards the middle resulting in little contrast between the lightest and darkest parts of the photo. As some cameras add contrast to your images automatically, it is better to use the RAW setting if possible and adjust the levels afterwards on your computer. Even if you don't have a RAW settting on your camera, adjusting levels can improve the contrast range.
The first time you take underwater shots be sure to leave the flash on if you don't want everything in the picture to be blue. Set the flash to 'forced flash' and this will alter the color balance ensuring the colors come out better. You'll find that most of your shots are taken with the subject close to the camera so try setting your camera to macro mode. After about two feet you will need to switch off macro mode. Also switch off the flash after 3 feet.
Whatever camera equipment you have, venture into the magical environment beneath the sea, and discover a whole new world under the water, one of strange beauty. Bring that world back with you as photographic memories that let you live there a little while longer. Fish, underwater flora, shipwrecks, seascapes, other divers, and even caves, there are so many exciting and unique photo opportunities under the sea's surface.