NIKKOR Optical Glass.

Lenses are one of those things that you know a lot of work goes into the construction of—or at least you assume it does, hence the price tag—but I’m always amazed by the craftmanship that goes into it when it’s presented for the viewing public. Leica published a couple of videos a while ago, and now Nikon Japan has a demonstration of the process of creating the glass itself used in their lenses.