PhotoPro: Ring of light

Midwinter is a frustrating time for the underwater photographer. Weather regularly sabotages plans for local dives and, unless we invest in long-haul exotica, it is often hibernation time for our underwater cameras. But just because we’re not getting wet, it does not mean we have to stop thinking about our photography. The winter break is when I come up with the ideas for next season’s shots and put my limited DIY skills to the test with kit to make new images possible. This month, PhotoPro is more Blue Peter than Blue Planet, as I am encouraging you to build a ring-flash for ten quid!

A ring-flash is a strobe that encircles your lens, producing light from all directions and giving a virtually shadowless illumination on the front of the subject. Ring-flashes are popular on land for portrait and macro photography, and a few have been developed for underwater use too. Underwater, they are suited to macro detail shots, and also for getting light inside crevices, tubes and even masks. They work well with translucent subjects, such as nudibranchs, sea squirts and so on, where the directionless light creates an optical illusion, making the subject appear to glow from within.

However, you don’t have to be a fan of film noir to appreciate that shadow is important in photography. It reveals texture and gives depth. So, illumination that eliminates shadows will never be our mainstay, and this has always stopped me investing in a commercial ring-flash.

I would have loved one for the few subjects they suit, but could not justify the purchase. Most are more expensive than standard strobes, and we still have to buy normal strobes (meaning more luggage weight too) for the majority of subjects the ring-flash does not suit.

So, instead of buying one, I decided to make one. Not a fully functioning ring-flash, but a ring-flash-shaped reflector box, powered by my strobes. This produces the characteristic ring-flash lighting, is cheaper than O-ring grease, adds little additional travel weight and gives the ability to swap back to standard lighting during a dive. It is not an original idea: I have seen it done on land, and the designs seem ideal for submergence with no moving or electrical parts. The entire system is intended to fill up with water quite happily.

I’ll summarise the design, but I won’t give a precise step-by-step construction guide, because the specifics will depend on your system. This is something that can be made for either a compact or SLR, although the scales are different. Furthermore, my craftsman skills place me firmly in the bodger camp, and I am certain many readers can create a far more refined version of this idea. After all, my ring-flash is made from a casserole dish.

The basic idea is very simple. It is a reflective chamber (I found the white of my casserole dish is fine) around the port with hole(s) in the side(s) into which the strobe(s) is fired and a ring-shaped, opaque window at the front, encircling the port, out of which the light shines. As you can see from the photo of my camera during pool tests, the reflective chamber and opaque window are about 25mm wider than the port. For the port on a compact, this should be smaller. I also fitted old neoprene wetsuit sleeves over the front of my flashes to stop any light spillage. And that is it.

The design works well and I have used it in Indonesia, Canada and Italy, where I took this month’s photograph (opposite). The most pleasant surprise was how easy the system is to use. Nothing to adjust, just shoot, shoot, shoot. Changing orientation is simple, with no strobes to reposition. This was particularly advantageous in the chilly waters of Canada, where I always feel less inclined to fiddle with everything and just want to bag the shot.

But there are a few negatives. Backscatter is much more prevalent because the light source is fixed very close to the port. This restricts its use to less than 50cm from the subject in clear water and less than 30cm in murky water, ideally closer still. It is also a technique to be used sparingly – because ring-flash lighting is so perfect, it gets a bit, dare I say it, dull. I can see it being highly suitable for a nudibranch fancier, who wants all his shots to have an identical lighting. But the more artistically minded underwater photographer should consider it the perfect tool for patterns, critters in crevices and translucent animals, but not one that should be overused.

So I say fight the frustration as the elements conspire to keep us out of the water this winter, and continue to enjoy the hobby by making plans and kit for next season’s killer shots. Few people have tried a ring-flash underwater and it might just yield that winning image. Ultimately, this is a useful accessory that can be built cheaply, even if your DIY skills are as limited as mine. And you don’t even need double-sided sticky tape. ■

IMAGE DATA

Yellow scorpionfish eye, Sardinia, Italy. Nikon D700 SLR. Subal housing. Sigma 150mm with Canon 500D dioptre. 1/320th at f/18. ISO 400. DIY ring-flash powered by twin Inon Z240 strobes.