With the pervasiveness of automation and mass production these days, one would assume that every aspect of any tech gizmo is put together by machines.
So you can imagine my surprise when I saw a Sigma employee slowly and carefully painting the AF/MF marking on a newly made lens component.
It was one of many things I saw during my recent visit to Sigma's factory in Aizu, Japan, that made me realise just how traditional this lens-making giant still is.
Sigma is the world's largest third-party lens manufacturer. Founded in 1961 by the late Michihiro Yamaki, it makes lenses for consumers to use with their Canon and Nikon DSLR cameras.
In recent years, it has started making cameras. Last month, it announced its first mirrorless camera with its sd Quattro series as well as introduced another groundbreaking lens with its new 50-100mm f/1.8 lens.
Mr Kazuto Yamaki, the founder's son, took over as the chief executive officer of Sigma after his father's death in 2012.
During my factory tour - with other journalists from France and Germany - Mr Yamaki explained how Sigma was founded not to make money but to provide jobs.
He recounted that an optics company his father was working with had become bankrupt, and its suppliers urged the older Mr Yamaki to start a new company in order to preserve jobs. "So my father founded this company to help these suppliers," Mr Yamaki said.
From seven workers when Sigma first started, it now has a workforce of 1,800 and an annual turnover of 43.1 billion yen (S$523 million). About 1,600 of its workers are employed at its only manufacturing plant in Aizu, while the rest are mainly marketing and sales employees working at the company's headquarters in Kawasaki.
Nearly 80 per cent of the staff are engineers, reflecting the "small office, big factory" philosophy espoused by Sigma's founder.
"That is how we can provide high-quality products at reasonable prices compared with other companies," said Mr Yamaki.
Sigma has kept its factory in Aizu when its competitors have moved overseas to save costs. In fact, it has been expanding the factory since it moved to Aizu from Tokyo in 1974.
From a humble one-block plant, it has expanded into a seven-block facility with a floor area of around 55,000 sq m, roughly the size of 71/2 football fields.
The factory's maximum output is 100,000 lenses a month.
However, Mr Yamaki revealed that it usually makes around 70,000 to 80,000 lenses a month.
Aizu, about 300km north of Tokyo, used to be an important political area in mediaeval Japan, but was shunned after its futile fight against the emperor during the last Japanese civil war around 150 years ago.
As a result, it has changed the mindset of the Aizu people. "The mentality of the people here is very different from other parts of Japan, especially Tokyo," said Mr Yamaki.
He said the Aizu people are very traditional, serious, diligent and persistent - attributes which come in useful for lens making.
In addition, all the suppliers for the factory are local or from northern Japan.
"If something happens, we can meet easily to solve the problems," Mr Yamaki said.
Sigma's Aizu factory strives to be "vertically integrated". He explained: "By that, I mean we do almost all the processes for the manufacturing of lenses by ourselves."
These processes include grinding and polishing raw glass into lens elements, making the screws, anodising the metal parts, painting, injection moulding and prototyping.
It was fascinating to see the Sigma lenses start life as unpolished glass before undergoing so many processes and assembled into the final product.