WE ALL AGREE that it is one of the quintessential underwater experiences, but one that few British divers actually get round to trying for themselves – diving in a giant kelp forest. I’d put it solidly in my top five, along with the adrenaline rush of coming face to face with a great white shark, feeling flabbergasted by the weird and wonderful critters on a muck-dive, being mesmerised by the rich reefs of Raja Ampat and playing with lively seals or sea-lions. 

In fact one of these experiences (sea-lions) is pretty common on kelp-forest dives and another (white shark) is theoretically possible, but best not thought about!
The inimitable Trevor Norton calls giant kelp “super-seaweed” and eulogises the diving experience: “The best way to be overwhelmed under water is to sink lazily into the tall forests of giant kelp. You can glide beneath the luxuriance of the fronds, slide between the stems and hide among the shadows below.”
What I love is that the dive-site and the photography starts immediately at the back-platform of the boat.
Giant kelp grows right to the surface and the skippers usually anchor the boat so that the dive-deck nestles up against the forest. You literarily step off the boat and are right in the dive-site until you resurface.
Giant kelp is a wonder of nature capable of growing up to 60cm per day and growing to 80m in length. It favours cooler, nutrient-rich waters and is found in southern New Zealand, Tasmania and South Africa, Tristan da Cunha, the Falklands and other sub-Antarctic islands, extensively in Argentina and Peru and, most famously, on the Pacific coast of North America.
For photographers the zenith is probably California’s off-shore Channel Islands, where clearer waters provide the chance to capture its full splendour.
While California is a very popular holiday destination for Brits, few remember that it is a dive-destination too. Particularly for those who are photographers, this is a big mistake!

THE GIANT-KELP forest doesn’t just provide an unforgettable backdrop for dives, it is also fantastically photogenic.
The habitat overflows with wide-angle and macro photo opportunities, although I’ll concentrate on the former here, because there aren’t really kelp forest-specific macro techniques.
The biggest surprise when you first raise your camera in the kelp forest is the light level. Despite the typically sunny Californian weather, the photosynthetic fronds of the forest suck up the light.
And when we try to light up the kelp with our strobes, it sucks up their output for good measure! Light management is therefore key to success.
The first challenge is making sure that we have enough light. This is an environment in which it is worth increasing the ISO. The latest cameras are incredibly capable in this regard and, enticingly, it enables us to take types of images in the kelp that just couldn’t be pulled off a decade ago.
That said, the rapid drop-off of light in the forest is usually more than the camera can cope with, and careless compositions make it is easy to blow out the surface, robbing the image of atmosphere.
One solution is to shoot with the light, which reduces the range we’re asking the camera to capture.
Alternatively, look for a thick surface mat of plants to hide the brightest part of the surface and expose for mid-water. The advantage of this approach is that the sunlight can look very attractive penetrating this golden backlit canopy.
Most photos in the forest require flash to light the subject. Powerful strobes on long arms are a big advantage when trying to light up bigger scenes, although be aware that you’ll end up with them tangled in kelp at some point.
The alternative approach in shallower water is to ditch the strobes and shoot with a filter. This approach really brings out the golden-brown colour of the kelp and is ideally suited to photographing the forest, but less so the colourful life within. It can also fail to freeze fast-moving subjects such as sea-lions.
A wide-angle lens is the other essential to open up the space in the dense forest, and the fisheye is best.
The only downside of using a fisheye is that it bends the kelp. Fortunately, kelp in the ocean is never straight, and as long as we compose carefully, this problem disappears.

THE STRONGEST KELP-FOREST photos rarely have the kelp as the main subject. The forest itself is both hard to light with strobes and more attractive as a background, setting the stage for an eye-catching foreground subject.
Most of the colourful life lives close to or on the seabed. On my dives I favoured the red gorgonian fans, as well as other species in orange and yellow.
Starfish, sponges and large invertebrates such as giant sea hares are also options. In certain areas the giant black sea bass can be the most amazing foreground subject.
Kelp-forest fish are curious and less territorial than coral-reef fish, which means that when we set up a shot, sooner or later, one will show up – shortly followed by another of a different species! The trick is to keep our eyes open and time our shots for when they are in the right position.
The bright orange garibaldi, a super-sized “you’ve-been-Tango’ed” damselfish, is certainly the star attraction, although during my visit their numbers were down.
Fortunately, the Californian sheepshead is a capable understudy.
Sea-lions provide frequent but unpredictable gone-in-a-flash encounters, while harbour seals are less energetic, but much rarer and certainly not as bold as British grey seals.
Both of these pinnipeds offer the advantage of encounters in shallower water, where light beams dancing through the canopy are more pronounced and easier to capture.
At shallower depths the forest is very photogenic, but it lacks the abundance of colourful invertebrate life, although kelpfish, kelp snails and large nudibranchs can be exploited.
The most reliable subject to use as a foreground at these depths is the kelp itself. The growing tips of a healthy plant are the most attractive part, with new fronds (like leaves) extending out of a line of golden gas-bladders.
The shot, kelp against forest, is one of the classic ways to capture this archetypal underwater experience.

Use the forest as a background, rather than photographing it as the main subject. Find a colourful critter (seafan, starfish or fish) and use it as a foreground, set against the rows of kelp.
The forest is dark, so be prepared to boost the ISO and drop your shutter-speed to accommodate it – you don’t want the kelp blending into dark waters.

Kelp grows upwards to the surface, so the most dramatic images are usually vertical compositions. Don’t forget to rotate your camera into the vertical format!
Close-focus wide-angle is the ideal technique for the kelp forest, because the short camera-to-subject distance minimises backscatter, while the wide view captures the grandeur of the habitat.

Managing dynamic range is an essential skill when composing images in the forest, because the range of brightness is usually much larger than our camera can capture. Areas that are too bright pull the eye from the main subject.
The trick is to frame so that the brightest and darkest areas are hidden from the camera by the composition, and then to correctly expose for the mid-light levels.

Caption Key

The clean, growing tips of kelp are especially photogenic, with lines of small gas-bladders.Taken with a Nikon D4 and Nikonos RS 13mm. Subal housing. Seacam strobes. 1/80th @ f/16, ISO 400.

Kelp forests provide the perfect background for a multitude of subjects, here with a harbour seal.Taken with a Nikon D4 and Nikonos RS 13mm. Subal housing. Seacam strobes. 1/125th @ f/10, ISO 400.

Shooting vertically upwards makes leading lines of the kelp plants.Taken with a Nikon D4 and Nikonos RS 13mm. Subal housing. Seacam strobes. 1/125th @ f/20, ISO 400.