Photo: Charles Hood Photo: Charles Hood Photo: Charles Hood

One of the hardest images to take underwater is an extreme wide-angle or fish-eye photograph. Unlike topside photography, red light underwater is absorbed at relatively shallow depths, followed closely by orange and yellow. So, for nearly all images taken underwater, photographers tend to use flashlight or strobes. The colour temperature of the strobe light is very near to that of the sun and restores the colours removed by the filtering effects of the water. This technique works well for close-up and macro photography. However, when we try to illuminate a large subject, even this light is either filtered by the sheer amount of water in between the camera and the subject, or the strobe's intensity isn't strong enough. A solution may be to use a complementary filter to remove the blues and greens and thus restore the natural-light colour balance.

UK underwater photographer and marine biologist Alexander Mustard decided to tackle this problem and has produced a set of filters designed to do exactly this.

So how do they work? Mustard explained that filters don't add colour, they subtract it. Therefore, what 'magic' filters do is restore the colour balance by removing the unwanted blue and green colour to match that of the already absorbed red light. The filters I tested are about the size of a ten pence piece and are designed to fit on the rear of a fish-eye lens. The only downside is that you have to set the white balance of the camera for each depth you are at. Although it's tedious, you get used to this after a while. The other consideration is that you have to shoot with the sunlight coming from behind the camera. What were the results? In a word - astonishing. The images are far more like those you actually remember seeing, rather than the artificial colours produced by a strobe. Two images demonstrate this well. One is of a red fluorescing anemone (see far left). The problem with these critters is that if you light them with a strobe they absorb the light and appear brown. Using the magic filter allowed me to end up with a true to life colour. The second image (see left) is of a giant kelp forest. As it was such a large area, I found it impossible to light the 30m-high stalks with strobes. The result was a green-looking kelp. However, with the magic filter the true brown was restored.

Magic filters do have their limitations. They can only be used with a digital camera - does anybody still shoot film? Furthermore, you must be able to 'white balance' underwater, which usually restricts the filters' use to DSLRs (digital single lens reflex). Also, they are designed to work only in the 1-20m depth range. Having said all that, they do allow you to get images otherwise unavailable to you by conventional means.

Priced competitively at under £20 each, or £30 for a set of three, magic filters are a must for anyone wishing to take large subjects in clear, shallow waters.

Verdict
Excellent way to restore natural colours
Value: 10/10
Performance: 9/10

Contact: PR Productions 020 8399 5709
Website: www.magic-filters.com