Filming Blue Planet III

Filming thousands of metres below the surface takes remarkable technology. Here's how the Blue Planet III team captured life in our oceans.

For Blue Planet III we travel right across the world. From the tropical seas to the polar regions and deep into the ocean's most remote realms. Every ocean habitat presents its own challenges. One week, crews battle scorching heat in the tropics; the next, they are working in temperatures well below freezing. There are rough seas, relentless winds, long days in waist-deep mud, sand finding its way into every piece of equipment, and the constant salty spray in your face! And that's only above the surface. Once we go underwater, the challenges are even greater.

Unlike filming on land, every minute underwater is limited. The underwater team constantly manages air consumption, depth, tides, currents and visibility, all while thinking creatively about the sequence they are capturing. What behaviour are we filming? What camera and lens will tell the story best? Where is the animal heading next? Every decision has to be made quickly, often in unpredictable conditions.

The ocean itself is often the biggest obstacle. A slight change in temperature, wind or current can transform a perfect filming location within minutes. On some shoots, visibility deteriorates so dramatically that crews can barely see the cameras they were operating, let alone the animals they've come to film.

For The Deep, the challenges are on a completely different scale. Achieving our ambitions means working alongside multinational teams operating some of the world's most advanced research vessels and deep-diving submersibles. These platforms support multiple scientific missions at the same time, so success depends on close collaboration and a shared understanding of everyone's objectives.

Perhaps the most unexpected challenge, and one that runs right across the series, is helping people fall in love with marine characters that are not immediately lovable. Animals such as whales, dolphins and penguins naturally capture our affection, but most ocean creatures are far less familiar. Their slippery, slimy bodies can seem strange, alien and difficult to relate to.

Through emotional, character-led storytelling, Blue Planet III reveals the personalities behind these unusual creatures, shining a light on the ocean's less obvious stars. Some of the most rewarding sequences come from animals that people might normally overlook, uncovering surprising behaviours that transform them into characters people will genuinely care about.

For this series, we push filming technology further than ever before, combining the latest camera systems with bespoke systems to capture underwater behaviour in ways that had never previously been possible. As you'd expect, all of the cameras we selected were the latest models, but sometimes off-the-shelf kit isn't enough.

Filming Blue Planet III is as much an engineering challenge as it is a filmmaking one. To capture behaviours never before seen on screen, our teams are constantly designing, testing and refining new technologies. From waterproof FPV drones that can fly through the spray of huge waves, to remote-controlled boats disguised as floating ice, to cameras lowered beneath drones and into the path of hunting tiger sharks, innovation runs through every part of the series. Not every invention succeeds, but each one helps us push the boundaries of what is possible and uncover new ways of telling the ocean's stories.

For Blue Planet II, a piece of equipment called the Megadome was developed to capture spectacular shots that combined views above and below the ocean's surface. For Blue Planet III, however, we wanted to bring audiences closer to our animal characters, so we reimagined the Megadome on a much smaller scale. This miniature version, which we called the Minidome, could fit inside a tiny rockpool and prove invaluable in helping us capture the intimate octopus story featured in Seasonal Seas.

On land, movement-triggered camera traps are crucial for capturing the rare and illusive behaviour of wild animals. Underwater, however, they simply don't work. Fish, seaweed, drifting debris and even the movement of the water itself constantly trigger the cameras. We encountered exactly this problem while filming sponge-carrying dolphins in Shark Bay, Western Australia. To film what was happening beneath the surface without disturbing or scaring them, we spent almost two years developing an underwater version of the camera trap. Although the idea sounds straightforward, designing it was anything but.

The system has to withstand long periods underwater without flooding and overheating, while continuously recording vast amounts of footage for up to 24 hours at a time. After countless rounds of trial and error, we create the 'Stonefish'. Without this custom-built piece of equipment, we would never have captured the remarkable behaviour of the sponge-carrying dolphins featured in the Tropical Seas episode.

Remote cameras are also essential in the deep sea. Much of The Deep is filmed using ROVs (remotely operated vehicles). But when working with an ROV, there is one major limitation: all you get is the view from the vehicle itself. We wanted more, we wanted to be able to show the ROV operating in the deep ocean, giving audiences a sense of its place within this rarely visited environment.

To solve this problem, Series Producer James Brickell and Producer Eva Spielvogel designed a 'deep-sea selfie stick' - a remote camera system rated to depths of 3,000 metres that we nicknamed 'Little Charlie'. Mounted away from the ROV, it allows us to capture cinematic shots of the vehicle at work in the deep, revealing both the scale of the ocean and the extraordinary technology that makes these expeditions possible.

From homemade prototypes to cutting-edge camera systems, every innovation has a single purpose: bringing audiences closer to the ocean. If Blue Planet III succeeds in revealing new behaviours, creating new connections with marine life and inspiring a sense of wonder about our blue planet, then every challenge, setback and breakthrough along the way has been worth it.