Canon fire
To celebrate 30 years of the EOS system AP Editor Nigel Atherton was given a privileged peek behind the scenes at the Canon EF lens factory in Japan
From March 1987 to 2017, Canon produced 90 million EOS cameras and 130 million EF lenses. It’s an astonishing gure which vindicates Canon’s decision back in the 1980s to abandon its popular FD mount in favour of the new electronic EF mount, rendering its then-entire, existing system obsolete at a stroke. Canon’s subsequent conquest and domination of the 35mm SLR market, followed by the DSLR market, is entirely due to that move, because the new mount laid the foundations for all the ground-breaking technology that followed.
To celebrate this milestone, AP was one of just two UK and four German publications invited to visit Canon’s global headquarters in Tokyo and tour its Utsunomiya lens plant, where its L-series lenses are made.
Canon’s Utsunomiya lens factory was built in 2005, and lies around an hour north of Tokyo by bullet train. It’s an imposing grey, low-rise slab of a building, surrounded by manicured lawns and car parks, all of which appear to be unblemished by even a speck of dust. Adjacent to the factory, on the same site, is the lens laboratory, where the research and development into new products takes place. We wouldn’t be visiting there!
A warm welcome
Three ags ew at the factory entrance: those of Japan, Germany and the UK, in our honour. At the entrance the factory’s senior management stood in line to greet us. The Plant Manager, Kenichi Izuki, who is responsible for the smooth running of the factory and its approximately 1,700 employees, led us to the meeting room where we were introduced to the brains behind Canon’s EF lens programme. Finally we donned our stripy jackets and soft shoes and passed through the security doors to where all the magic happens.
The business of designing and manufacturing lenses is an incredibly exacting process. That’s no surprise, but just how exacting is something that you might nd dif cult to get your head around. Canon’s 4K/8K broadcast lenses, for example, are built to a tolerance of within 30nm, or 30 millionths of a millimetre. To put this into perspective, if you could enlarge a polished lens element to the size of the Maracanã Stadium in Rio de Janeiro, the deviations in surface accuracy would have to be less than the thickness of a plastic bag!
But we’re getting ahead of ourselves. Every Canon lens starts life not in the factory but in the R&D labs across the road. Indeed before even that happens, there is the market research conducted by the Business Planning Department at Canon’s Tokyo HQ, into what is required by the customer.
The design phase
So where do the ideas for new lenses come from? I posed this question to Canon’s senior lens designers, Manabu Kato, Tetsushi Hibi and Seiichi Kashiwaba.
‘We have an ideal lens, as a vision, for each of the categories that we operate in,’ they explained, through a translator.
‘We also spend a lot of time listening to our customers, and this lets us know what sort of things they are looking for. At the same time we look at the technology we have in house, and we identify where the
gaps are between what we would like to do and what we can do. That is the engine that drives our technological development.’
Once the Business Planning Department are satis ed that there is a market for a lens, and that it’s technically achievable and economically viable, the head of Canon’s lens division, Naoya Kaneda, gives the green light for the concept to go into the product design phase.
Computer software is used in their design process, but rather than work with existing off-the-peg applications, Canon has built its own software. ‘We felt that we could do better using our own in-house expertise,’ says Mr Kaneda, frankly.
Designing a new lens isn’t just about deciding how many elements it will have and what shapes they’ll be, but also the composition of the glass itself. Glass can be made from a variety of metallic oxides and other ingredients. The designers have extensive knowledge of the chemistry and composition of different types of glass and the effect this has on optics. Combining different types of glass elements within a single lens to achieve the desired result is part of the skill of lens design.
According to Kengo Ietsuka, the manager of the Business Group, it’s relatively easy to make a high-quality lens if you don’t have to think about the size and weight of the lens, but for Canon the challenge is about achieving a balance of size, weight and quality. But for Shingo Hayakawa, Kaneda’s deputy, the biggest challenge when producing L-series lenses is the extra durability that they require. ‘It’s one of their de ning qualities,’ he says.
Since none of the machinery required to make a new lens has been built yet, the early prototypes are made largely by hand.
‘If it includes a new piece of technology that we’re introducing for the rst time, such as when we developed the IS system, we’d do a partial creation of the prototype to see how it performs, and ne-tune the speci cations accordingly,’ explains the team. ‘If we’re con dent about the design and how it will work we will try to create as nished a prototype as possible.’
In these early stages there is constant back and forth communication between the lab and the factory. ‘We work closely with the plant to overcome the challenges that we will face in manufacturing the lens,’ continue the designers. ‘We don’t just give the factory a design and say, “Here, make this.” For example, when we developed the EF85mm f/1.4L IS USM, the biggest challenge was that the IS unit for this lens was very large; so it took longer to create than average.’
The next steps
When a prototype is created it does not go into production straight away. ‘The production timeline for a lens is a matter of years rather than months,’ explains Mr Kaneda. ‘Once we have designed the lens and made the prototype we spend a lot of time testing and listening to feedback from professional photographers. We have testing areas where minute adjustments are made to the optics, and we also have an area where we hit the lenses and drop them on the ground to ensure that the nal products have the highest standards of durability. For example, if you compare the Mark I of the EF24-70mm f/2.8L USM lens with the Mark II version of it, you will see that the durability has been greatly increased.’
Before a new lens goes into production, the machinery to make it rst has to be built, and here Canon also has its own in- house team – the Production Engineering department. According to Plant Manager Mr Izuki the biggest technical challenge for the manufacturing team is achieving consistency. ‘All the lenses that come off the line will be within a speci ed level of tolerance, but making each one as close to identical as possible is very dif cult. We strive to achieve as little variation between lenses as possible, so we do a lot of ne-tuning on
the production line.’ Canon has over 90 lenses in its current range, and it would be impractical to be making all of them all of the time, so Mr Izuki is given a production schedule which speci es how many of which lenses need to be made over the next month. ‘There are some lenses, such as the TS-E tilt/shift ones, where there is a team working on a special line spending two hours a day making these. But this is the exception,’ he says. ‘Mostly we have parallel lines running continuously all the time.’
Making the lenses
There are ve stages to turning a lump of glass into a Canon lens. Stage 1, Rough grinding: this turns the lens from a rough tablet of frosty glass, called a ‘cake’, into a curved surface of a speci ed dimension. Stage 2, Smoothing: where the lens is ne ground to the proper degree of roughness and surface curve, using a curved drum embedded with diamond pellets. Stage 3, Centering: at this stage the optical axis of the lens is adjusted, by ne-tuning the curvature of the lens. Stage 4, Polishing: here the surface of the lens is polished using a rotating polyurethane pad until the lens becomes transparent. Stage 5, Inspection: the lens is tested and inspected to ensure it meets the required standard.
With most of the smaller, non-aspherical lenses, this process is now automated using a machine designed and built by Canon’s Production Engineering division. This machine cleverly measures every single lens that goes down the line – and applies optical corrections as it goes. During our visit we watched a machine that produces elements for the EF16-35mm f/2.8L III USM lens in around 30 minutes.
But the more specialised lenses, like the super-telephotos and the 4K/8K broadcast lenses, are still made largely by hand by craftsmen with decades of experience. Craftsmen like Toshio Saito, who has gone beyond the title of ‘meister’ to that of ‘Takumi’, or master craftsman, for his 30-plus years of lens polishing experience, and now heads that department. Indeed, most senior staff seem to have spent their working lives at Canon, which perhaps explains the palpable sense of loyalty and pride in everyone we met.
Canon’s obsession with perfection and ne detail was brought home to me when I happened to glance at one of the six framed prints on the wall of our meeting room and recognised Brighton’s West Pier. ‘That’s a coincidence, I live in Brighton,’ I said, before realising that it wasn’t a coincidence at all. Six guests, six prints, each one representing one of our home towns. At that moment it became clear why Canon has managed to achieve such a global domination of the camera and lens market for so long.