ARTICLE

Why white? The story behind Canon's iconic white lenses

Canon's super telephoto lenses may be instantly recognisable thanks to their distinctive white paint, but the technology behind the coating is just as remarkable.
Rows of white telephoto lenses point towards the pitch at the side of a sporting event.

Sporting events around the world inevitably exhibit a few key ingredients – skill, excitement, drama, and rows of gleaming white Canon telephoto lenses.

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.
 Lucia Griggi, wearing a woollen beanie and cold-weather coat, sits on the ground photographing Highland cattle with a Canon EOS R6 and Canon RF 70-200mm F4 L IS USM lens.

Wildlife and adventure travel photographer Lucia Griggi took a Canon EOS R6 with the compact, white-painted Canon RF 70-200mm F4 L IS USM lens on a journey through Scotland's dramatic Inner Hebrides. Find out more about her experiences on this first shoot with the lens. © Andrew Ford

The Canon RF 600mm F4 L IS USM super-telephoto lens, with lens hood.

The latest RF super-telephoto lenses, including the high-performance Canon RF 600mm F4 L IS USM, are finished in Canon's latest white paint featuring a specially developed heat shield coating. Just as importantly, the lens hood has the same protective coating, ensuring a consistent temperature between the lens and the attachment.

So why does Canon make its telephoto lenses white? The reason is simple: heat. When photographers are outdoors, under the blazing sun, even a slight warping of the lens components due to heat can have a negative effect on the resulting photo. And holding a hot lens for long periods of time is also a burden for photographers.

Even in the harshest conditions, Canon wants photographers to get the best possible shot every time. This is the motivation behind Canon's white lens paint. White is the most effective colour for reflecting heat.

However, Canon's lenses aren't actually pure white. Although white lenses are superb at resisting heat, they can also reflect light particularly brightly, interfering with the shots of other photographers nearby. That's why Canon chose to adopt a slightly off-white shade – a softer white that doesn't reflect light quite as harshly. And in fact, Canon's white lens paint has evolved over the decades.
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Sports photographer Eddie Keogh in a sports stadium holding a camera with a Canon EF 600mm f/4L IS III USM lens attached, with another camera and white lens hanging around his neck.Sports photographer Eddie Keogh in a sports stadium holding a camera with a Canon EF 600mm f/4L IS III USM lens attached, with another camera and white lens hanging around his neck.

Sports photographer and Canon Ambassador Eddie Keogh shooting with a Canon EF 600mm f/4L IS III USM lens, one of the first two lenses to feature Canon's new white heat shield coating in 2018.

The Canon RF 400mm F2.8L IS USM super-telephoto lens.

As Canon's telephoto technology has advanced, producing extraordinary lenses like the Canon RF 400mm F2.8 L IS USM, the protective white paint that surrounds it has become increasingly important. In addition, the incredible resolution of the sensors in today's cameras only adds to the need for lens reliability and consistency.

More than half a century of history

The story of Canon's white lenses began more than 60 years ago, in 1960, when Canon adopted white for its broadcast camera lenses. In 1976, white was first used for its SLR camera lenses, to reflect heat and minimise thermal expansion and contraction.

This is particularly valuable for lenses made with heat-sensitive materials such as fluorite. "Optical engineers have known for a long time that fluorite lenses have many benefits," Mike explains. "For example, fluorite's very low refractive index greatly alleviates the critical problem of chromatic aberration, which is inherent in glass lens elements. The only catch is that natural fluorite crystals, because of their small size and impurities, do not meet all the requirements for a camera lens. In the 1960s, Canon pioneered synthetic fluorite lens elements, and became the only manufacturer to incorporate fluorite in its autofocus lenses for SLR cameras. However, synthetic fluorite is just as susceptible to heat as natural fluorite. So the white finish helps Canon lenses deliver the benefits of fluorite and reliably give outstanding optical performance even in hot sunlight."

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"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."
An illustration showing conventional white paint, reflecting some heat but also letting some through, compared with Canon's new white coating, reflecting more and letting less through.

In the past, Canon has adjusted the colour of its white paint (left) using the black of carbon black (represented by the black spheres) and the white of titanium oxide (the white spheres). However, carbon black strongly absorbs infrared rays. Canon's newly developed heat shield coating (right) replaces carbon black with infrared reflective pigment (the blue spheres) and contains titanium oxide coated with silica (the coated white spheres), with the result that it reflects away a much higher proportion of infrared rays in sunlight.

Evolving improvements

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."
Photographer Matthew Joseph lies on his side at the water's edge, shooting with a Canon EOS R camera and Canon RF 70-200mm F2.8 L IS USM lens.

Photographer Matthew Joseph shooting rowers on the River Thames near London with the Canon RF 70-200mm F2.8 L IS USM lens. This lens, released in 2019, was the first RF lens with Canon's new heat-shield white coating. © Julian Love

A thick white liquid drips from a spatula into a jar.

It may look unremarkable, but Canon's latest white paint is packed full of heat-shielding technology that can keep a telephoto lens significantly cooler than it would be otherwise.

New generation

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."

Írta: Mark Alexander and Alex Summersby


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