The evolution of Canon's Eye Detection AF technology

Modern digital cameras feature autofocus that can not only automatically track moving subjects, but even track those that move at great speed. Canon has continued to push the boundaries, developing AF technologies that are not only capable of tracking faster movement but also a greater variety of subjects, including dogs, cats and birds. But it didn't stop there – Canon strove to develop AF that can remain focused on subjects as small as a bird's eye.

The latest iteration of Canon's EOS iTR AFX system, built on deep-learning artificial intelligence (AI), enables the latest cameras including the Canon EOS R3, EOS R5 and EOS R6 to recognise and track subjects with new levels of accuracy. The technology grows out of years of development.

To train the AI to recognise such a difficult subject, a vast amount of data was required. Canon gathered a huge variety of images of numerous species of birds in every imaginable position – resting, in flight, with wings spread for take-off, wings flapping, and wings folded in a dive. Then, it was necessary to teach the AI what was not a bird – during development, all manner of subjects were mistakenly identified as birds, including flowers, letters on signs, and outstretched human hands.

Step by step, mistakes and misidentifications were corrected, painstakingly building an accurate system with an outstanding hit rate. Of course, that wasn't the end of the development process. The next step was to refine the quality of AF detection in real-world use.

"The very first time we tested Eye Detection AF with photographers, we went to a safari park," says Canon Europe Senior Product Specialist Mike Burnhill. "On the way in, there was a black bird splashing about in a puddle. We pointed the camera at it, and it locked on to the black eye of a black bird in muddy water. It was amazing. The photographers were sold straight away."

Animal eye detection and tracking AF is only one part of Canon's intelligent autofocus system, which delivers a whole range of benefits including outstanding low-light AF performance and class-leading AF acquisition speeds. Thanks to Canon's Dual Pixel CMOS AF II technology, every pixel in the sensor can be used for both imaging and AF, which means the AF can acquire and track subjects across the entire frame, despite obstacles and distractions. "Because every pixel can both focus and take an image, they don't have to be one or the other," says Mike. "They are both. That's the magic thing. And they provide so much data, it gives us the ability to do all kinds of stuff, like focus right to the edge." The processor scans the entire scene up to 120 times per second, evaluating out-of-focus areas as well as in-focus areas, anticipating when objects might cross the path of the subject in order to keep tracking the subject without interruption.

The result is autofocus capable of detecting the eye of a bird in flight and remaining locked on to it.

For Jonas, out in the field, this radical leap forward has been game-changing.

"Before, I was stopping down to f/5.6 or f/6.3 just to have some extra depth of field to get the focus right. Now, with Eye Detection AF, I can really open up the aperture," he says. "I can go down to f/4 or whatever my lens is able to do. Not only does it enable me to shoot for an hour longer, it means I can get really nice backgrounds and foregrounds. It opens up a lot of things."

Animal Eye Detection AF has also revolutionised where Jonas can photograph. Before, he would tend to limit himself to open fields where he could get a clear shot, but now he goes wherever the owls go. "Now, I can take more creative shots by including foreground grass and other natural elements, because the autofocus will have the bird covered," he says. "That's a big difference for me, because now I can take action shots of the owls hunting in the deep forest without the trees interrupting the autofocus. That gives me opportunities."

Finally, Eye Detection AF has reliably delivered remarkable results. "These days, it's more rare to have shots end up out of focus," Jonas says. "If I have an owl flying straight towards me, I'll have 18 out of 20 pictures tack-sharp. It means I can select the perfect angles of the wings and the best composition."

Jonas says Canon's animal Eye Detection AF opens up new possibilities for him, enabling him to shoot almost without limits, and he still finds it astonishing.

"How can you find a black eye on a black bird, on a cloudy day, with distracting backgrounds?" Jonas asks. "How is it possible? At first, I didn't believe it. But Canon has nailed it. It's amazing."