Zeiss makes plenty of chinesium products but they do own or at least did own Schott Glass Werks. Swarovski and Leica spec out lenses and prisms and apply their proprietary coating on them but don't manufacture "glass", and it's doubtful they manufacture all the internal components either. We just don't have a say when we purchase because none of these companies are going to declare where point of origin concerning their products and what % is sourced from China.
Yes, Schott is owned by the Carl Zeiss Foundation--but that doesn't mean all Schott glass is made in Germany. There are dozens of Schott factories around the world, including three in China....
