With the natural world under serious threat, the powerful investigative work of photojournalists such as Canon Ambassador Brent Stirton on wildlife conservation issues, sustainability and the environment has never been more important.

Brent's work for international organisations including the Gates Foundation and Human Rights Watch, as well as publications including National Geographic, Le Figaro, GEO and Stern, has helped to raise the profile of conservation issues among audiences worldwide. As he says, "I'm in the business of influencing opinion".

In recent years his wildlife-related work has included stories on the rhino horn trade, pangolins in crisis and gorilla poaching. He is a Senior Correspondent for Getty Images, and has been involved with the New Big 5 project, set up by fellow photographer Graeme Green. The New Big 5 is a global initiative supported by photographers, wildlife experts and conservationists, including Dr Jane Goodall, with the protection of endangered species at its heart.

Here, Brent tells us how taking part in such initiatives, and capturing "irrefutable evidence" of the plight of animals in wildlife photo stories such as his graphic and upsetting documentation of rhino poaching, help him to ensure that action will be taken to protect them.

"The number one starting point is meeting people who need help with their project. If they need coverage to promote what they're trying to do, I try to offer that and be of service to the issue they're working on. I'm mostly looking for things people don't know about, so I can produce work that isn't already out there and is saleable."

"I did a story on pangolins which was very challenging. Smaller animal groups are disappearing at a huge rate – we're losing 40-60 species a day – and pangolins represent that situation. As pangolin scales are used in traditional Chinese medicine, I had to get to China. Reporting on the illegal wildlife trade is complex and when I was interacting with the criminal element, I had to do it very carefully to avoid compromising my Chinese partners.

"My greatest fear with these stories is not getting a key picture and not being able to tell the complete story. I'm in the business of influencing opinion, so I need to present evidence of what's happening that's irrefutable, and to place that evidence in the hands of power brokers, so hopefully action will be taken."

"If you take people into the wild and place them around wild animals for long enough, they see the value of wildlife. Part of my job is to provide that experience vicariously and also to talk about what's happening to so many creatures and how that's wrong. Animals can't speak for themselves, so there's an element of trying to do that for them."

"Until recently my main bodies were the Canon 澳门现金网_申博信用网-官网 and the Canon EOS-1D X Mark III, but I recently had the opportunity to use a Canon 澳门现金网_申博信用网-官网5 and from what I've seen so far, it will become my main camera, no question. This is the first camera which gives me the detail of really high-resolution files while also providing the low-light capabilities I need, plus the ability to pull back shadows and have a really amazing dynamic range."

"For the way I work, the bottom line is, I need to be able to walk with [the camera]. Previously I'd be carrying up to three camera bodies, but now it will be purely the two Canon 澳门现金网_申博信用网-官网5s. The camera is smaller and lighter, attracts less attention, it's weather-sealed, and the silent shooting facility will be very useful to me. I think the Canon 澳门现金网_申博信用网-官网5 is the best camera in the mirrorless world.

"In terms of lenses, I'm using the new Canon RF 28-70mm F2L USM, which is an incredible piece of glass. It's absolutely the equivalent of the best primes that are out there. The Canon RF 50mm F1.2L USM is an incredible lens too. I really do think all the RF lenses are a step up – they're in a different class to anything else in the mirrorless category. I'm now getting 95% of my photos in focus at f/1.2 and that has never happened before. For that factor alone, it's worth switching to RF lenses."

"I would say look for stories locally first. If you do that, you can go back to your story and refine it and it doesn't have to cost you a lot of money. I'd also suggest looking at the non-governmental organisations and charitable organisations that work in your area. Working with them gives you a way of placing pictures, and of being of service to them.

"I'd also say you don't need the latest and greatest kit when you're starting out, but what you do need is reliable kit. Buy the best glass you can, but don't buy a lot and put money instead into your production. It's better for you to finance what you're doing than to buy heaps of kit that just sits on your shelf. Just ask yourself two questions, in this order: What do I want to do with my photography? And what do I really need to do it? The more successful you become, the more kit will be important, because it will give you more options."

"There are a lot of good, admirable people out there trying to work on preservation issues, and I'm optimistic that this particular strain of human will continue. Ultimately, I'm hoping that a new green economy evolves. We're beginning to see that the natural world is valuable on so many levels. If we look after wildlife and wild spaces, I believe there's a great potential for them to look after us, both economically and spiritually. There's no question, if we wipe all those animals out, we're next. We need them and they certainly need us. We've been doing a pretty good job on failing them so far.

"In the countries where wildlife crime occurs, it's often about the exploitation of very impoverished communities, and a lot of my photography is about those communities as well as wildlife. I'm a real believer in the idea that if you don't look after those people, there's no hope."