Samyang optics is nothing to do with samyang corp (that does food and chemical products). Samyang-dong is a neighborhood in Seoul. Dumbass. They only do optics, and have done since 1972.
Fuji make cosmetics & industrial cleaning chemicals
Samsung make kitchen countertops
Canon make electronic dictionaries
Nikon make stem cell medicines & 3d printers
Olympus make plastic cutlery & face cream
Sony make TV shows
Panasonic make real estate
Leica camera actually broke away from the leitz parent company and only really do optically related stuff these days, but they used to do all sorts of medical devices, such as a sample slicing machine in a lab I used to work at.>>3949559
Kia are part of Hyundai, I'd happily drive a genesis g90. Mercedes are a subsidiary of Daimler, smart cars are their Kia, and arguably much worse.>>3949676
Other way round, they manufacture for numerous brands including rokinon and vivitar.