Camera advertising falls into a number of predictable tropes... "flirty fashion shoot", "EXTREME! SPORTS!", "hipster urbania", etc. However, one trope that gets repeated often happens to be one of the most meditative and calming... the process of how lenses are manufactured. The ideal selling point is the precision and rigour that the manufacturers put into creating camera lenses, so the pacing is often meditative and deliberate. These are often some of the most fascinating videos that the camera companies produce.
It goes without say that you can't mention lenses without mentioning Leica:
If you are unfamiliar with the manufacturing process, you might be struck by how much hands-on work the Leica video alludes to. Leica is a low-volume manufacturer, so a greater reliance on human assembly is expected, but this is true of much of the camera world. Camera parts are intricate and numerous, even when the scale of automation is increased, the necessity of human skill never goes away.
Moving on to the Sigma factory:
Sigma only has one factory in the Aizu area of Japan, in the western most part of the Fukushima prefecture. Speaking of "tropes", you can see the cultural difference between the Sigma video and the the Leica video. There is a marked "Japaneseness" that comes through in this video, more so than from the other Japanese manufacturers. The Leica video carries with it a certain industriousness that you might stereotype Germans with, while the Sigma video has the pacing of a meditative interlude in the middle of a Hayao Miyazaki film. Here's the followup movie:
Note how the factory shots are interrupted by cuts of Japanese countryside. This would make little sense in the context of western film-making, but the late Roger Ebert did a wonderfully simple explanation of the role that the silent cutaways played in pacing and punctuation in Miyazaki's films.
In case you were wondering if the the stereotypical presentations from the different countries was merely a coincidence, have a look a the Carl Zeiss video for their Touit lenses. If the austere aesthetic (black and white!) weren't enough, the seriousness of the soundtrack is certainly clear about what impression Zeiss wants to leave with you about their manufacturing. However, if you are keeping score, the Touit mirrorless lenses for Sony and Fujifilm are actually made in Japan through a partnership with Cosina.
Moving on to the Fujifilm factory, we get a softer, gentler presentation. Though the footage follows the same "look at our precision and craftsmanship" path that the other companies have followed, the pacing is unique... it's practically "down home". If we were being honest, the music and pacing aren't typical of Fujifilm's promotional videos, which tend to lean slightly more to the tech/features side of advertising.
Finally we have Nikon's commemorative video for the 80th anniversary of the Nikkor line of lenses.
Nikon's video is quite satisfying, as the visual flow from raw material to finished product gives you a good sense of what goes into lens manufacturing. The techniques and processes illustrated are depicted or alluded to in the other videos, but Nikon did a wonderful job of stepping back from selling the company and letting the lenses speak for themselves.
So yes; good lenses can be extraordinarily expensive, but consider the time and effort required to produce them.