From rugby to motor racing, from swimming to tennis – whatever the sport, major sporting events around the world have one thing in common: rows of photographers with white Canon super-telephoto lenses. They're so well established, they almost define the sidelines in many sports.

"There's a perception that the big lenses at sporting events should be white. That's what you expect to see," says Mike Burnhill, Professional Imaging Product Specialist at Canon Europe. "Even in sports computer games, the animated photographers around the virtual pitch have white lenses, because that's what you see in real life."

It's not just sports, of course, where this is true, but also photojournalism, nature and wildlife photography – wherever telephoto lenses are the norm, you'll see the iconic Canon white lens paint. It's been that way for decades, and continues in the latest Canon RF super-telephoto lenses, the Canon RF 400mm F2.8 L IS USM and Canon RF 600mm F4 L IS USM. But have you ever stopped to wonder: just why are Canon lenses white?

There is actually a very important quality-related reason for that distinctive Canon white lens paint, and the story behind it is a tale of innovation in pursuit of imaging perfection.

"Back in the early 2000s," Mike recalls, "when people were shooting with the EOS-1D at the Australian Open, there were complaints about autofocusing performance, with photographers coming into the media centre saying the cameras weren't working. The cameras were tested and everything was fine, so a technician went out and sat with the photographers to monitor the temperatures on the equipment and see what impact the heat was having."

Sitting in the same position, with the intense Australian sun beating down, the photographers and their kit became extremely hot. "It was like sitting on a sunlounger for a couple of hours," Mike explains. "The photographers weren't moving, and lenses were only pivoting left or right, so they warmed up quite a lot." It was the extreme heat that was affecting the autofocus system within the lenses.

"It's having those unique experiences that can bring the germ of an idea," Mike says, "from which you can create a problem-solving technology that has a bigger impact on a wider range of people."

Just like Canon cameras and lenses, the Canon white lens paint has been improved continuously over the years. In 2018, Canon's white lenses underwent another evolution with the arrival of a new heat shield coating.

Canon's primary objective was to create a white paint with better-than-ever heat shielding. Of course, that wasn't the only goal – the new coating also required abrasion resistance to prevent scratches from rough handling or use in various outdoor settings, and it had to resist discolouration even when exposed to sunlight for long periods of time. It also needed to feel sufficiently grippy but not abrasive in the hand, all while appearing "Canon-like" because the white was a key element of the company's brand identity.

Canon researched and tested various types of heat-shielding coating, including those used in the construction industry, but these materials didn't have sufficient rigidity to deliver the durability, vibration resistance and shock resistance that photographers needed – just a small bump would result in damage. Canon realised it would have to develop its own coating materials.

At the same time, the continuing development of camera and lens technologies themselves made heat stability an even greater priority once again.

"When we arrive at the latest generation of lenses, the journey comes full circle," Mike says. "Making lenses lighter means they have less mass and, in some ways, are more prone to the effects of heat. Camera resolutions are higher as well, so any small changes in lens performance can become more significant than they would have been in the days of film or at lower resolutions.

"As a result, we've developed a new white paint that reflects infrared light so well, it reduces temperature rise by 20% compared with the conventional coating material."

Canon's cutting-edge new white heat-shield coating appeared on the super-lightweight EF 400mm f/2.8L IS III USM and EF 600mm f/4L IS III USM lenses, released in 2018, then on the RF 70-200mm F2.8 L IS USM in 2019 and the RF 70-200mm F4 L IS USM. It features on the most recent Canon RF super-telephoto lenses, including the RF 600mm F4 L IS USM and RF 100-500mm F4.5-7.1 L IS USM, and also on associated lens hoods for super-telephoto lenses.

"If you've got a lens hood not being protected from the sun and therefore absorbing heat," Mike explains, "you'll create a heat haze inside the lens because the lens hood will get warm while the temperature inside the lens will be different. It will cause a haze – the mirage effect. So it's important to coat the lens hood with the paint as well, which is often forgotten about.

"We look at the little things that you wouldn't realise could have an impact but once you say it, it kind of makes sense," he concludes. "You need that experience to be able to create the tools that make a professional photographer's life easier."