The main difference is that German SCHOTT glass has slightly better light transmission.
German Schott B270 optical glass is highly resistant to solar radiation and offers high transmittance in the visible wavelength range. It also has high chemical stability and a fire-polished surface providing excellent image sharpness. The Japanese Optical glass is also a very high-quality optical glass with a very similar light transmission – 99.6% versus the German Schott B270’s 99.8% light transmission.
It is very hard to see the difference in image quality unless using telephoto lenses (focal length >100mm) or enlarging images to be printed in large formats.
What is Schott Glass?
Schott AG is a German multinational glass company specializing in the manufacture of glass and glass-ceramics. Headquartered in Mainz, Germany, it is owned by the Carl Zeiss Foundation. The company's founder and namesake, Otto Schott, is credited with the invention of borosilicate glass.
What is optical glass
Due to its exceptional level of clarity and durability, optical glass is the most commonly used material for a wide variety of optical applications, including: Lenses for analytical and medical equipment. Photographic lenses. Windows for optical systems and instruments.
Benefitting from well over a century of experience in the development and manufacture of high-quality glass products, Instrument Glass offers a huge portfolio of optical glasses for a vast range of commercial, industrial and scientific applications.