How Canon decides which lenses should come to fruition?

Satoshi Maetaki (left) and Yutaka Nakamura (right) holding the Canon RF 14mm F1.4 L VCM and RF 7-14mm F2.8-3.5 L Fisheye STM, respectively. Photo: Mitchell Clark

Last year, we had the opportunity to tour Canon's lens factory in Utsunomiya, to get a look at how the company produces its optics. This year at CP+, we had the chance to talk to some of the people who play a part in designing the lenses made there: Satoshi Maetaki, general manager of the Optics Technology R&D Center and Yutaka Nakamura, assistant manager at the IMG Products Planning Center.

Our conversation largely centered around two of the company's latest releases, the RF 14mm F1.4 L VCM and the RF 7-14mm F2.8-3.5 L Fisheye STM, but we also got to talk about some of the things the engineers consider when designing a lens, some of the tools and tech that helps them with that process and how they decide which lenses to work on.

Considering what lenses to make next

Nakamura says the process for deciding what lens to make next is a holistic one, based on several factors. "We always consider: 'what is the ideal lens lineup?' That’s always in our mind," he says. "It’s not just the market environment or the user’s feedback. We also have to consider the possible future advancement of our core technologies, and how consumers’ shooting styles will change."

"We always consider: 'what is the ideal lens lineup?'"

While many of Canon's recent lenses have been full-frame designs, in our interview with Canon's top executives, Go Tokura, Executive Vice President and Head of Canon's Imaging Group, said the company is still interested in crop systems. "We won't stop exploring the field of APS-C lenses," he says. "Our principle is both full-frame and APS-C. We will continue to explore."

Advanced materials, corrections and simulations

Once they determine what lens to make, the engineers and planners have to figure out how to actually build it. According to Maetaki, the decision on whether to use digital distortion correction is made at the very beginning of the process, as was the case for the 14mm F1.4 L VCM. "We developed this lens under the precondition that distortion correction is to be done on the camera side," he says. "Because some of the correction can be done by the body, the lens can be smaller."

"We developed this lens under the precondition that distortion correction is to be done on the camera side"

As with many other lens makers we've talked to, Maetaki said special elements like Canon's BR and fluorite lenses are especially important when it comes to making a high-performance lens that's still relatively compact.

He also says that Canon is taking advantage of recent advancements in simulation tech for lens designs. "At the time of development, we have a better idea of how it’s going to be post-correction. Thanks to the development of the simulation technology, we can select the optimal design." As the company designs the lens, it can run simulations in tandem with the physical design work it's doing.

AF motors

For modern mirrorless lenses, choosing which kind of actuator to use for the autofocus is also an essential part of the process. According to Maetaki, the decision is made on a case-by-case basis; sometimes the company will choose an autofocus technology based on the optical design, other times the type of autofocus actuator may influence the lens' construction.

"Simply put, we select the motor depending on the concept of each lens," says Nakamura. "Is it for professionals, for high-end amateurs, entry-level? Or is it specialized for still images, or a hybrid between stills and video? Also, price range is important for us to consider. And focal length, the maximum aperture… Based on all these elements, we’ll decide which motor or actuator is most suitable."

In the case of the 14mm F1.4 L VCM, the company went with the namesake voice coil motors because of their ability to move the lens's relatively large and heavy elements. And even though the RF 7-14mm F2.8-3.5 L Fisheye STM is a modern version of the DSLR-era EF 8-15mm F4L Fisheye USM, Canon decided not to go with the ring-type USM motor again. According to Nakamura, this was a lesson it applied from a previous lens, the RF 10-20mm F4 L IS STM, from 2023.

"That was an ultra-wide lens that had the STM as well," he says. "That let it be compact with quiet, speedy, smooth autofocus. We took that lesson and applied it to this model."

Making a line of lenses the same size

The lenses in Canon's VCM lineup have very similar dimensions to make it easier to swap between them if you're using a gimbal or other video setup. Image: Canon

One notable aspect of Canon's F1.4 VCM lineup is how all the lenses are all very similarly-sized, from 14mm to 85mm. Nakamura says this is so video shooters can use all the same accessories, such as ND filters, follow focus units and rigs, even when switching between lenses. "That’s why we stick with the same barrel size or diameter, so those accessory changes don’t become a burden. So this is one of the determining factors when we’re deciding to add a lens to the lineup. We have to consider all this, including the shooting styles of our users."

According to Maetaki, achieving this isn't actually as difficult an engineering challenge as it might seem. "With current focal lengths, it’s not much of a problem," he says. "If the focal length becomes even longer, the difficulty level goes way up. Because when that happens, the diameter of the glass becomes larger, so it’s harder to fit." He says that from 14mm to 85mm it's fine, but perhaps that means we shouldn't hold our breath for something like a 100mm entry in the F1.4 VCM lineup.

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