I am learning, quote:
"All
Discovery scopes offer lens quality far above expectation for the price range. All lenses are Fully Multi Coated (FMC) to give bright colour, edge to edge sharp images, in all light conditions.
Discovery ED range uses Japanese FCD100 HOYA glass lenses that provide extremely low chromatic dispersion and a bright, sharp image
Additionally some models use Lanthanum glass is used in many high end optical instruments as it offers better light transmission and many advantages similar to ED glass, these are fitted to the
Discovery HS 4-14×44 and
HI FFP scopes.
You will also hear about ED glass lenses. ED means Extra-low Dispersion and refers to the composition and optical properties of the glass used for the lenses.
Using specially formulated rare-earth compounds these lenses greatly reduce chromatic aberration (colours not all coming to focus in the same focal plane) to give sharper, better colour, images.
Discovery ED range uses Japanese FCD100 HOYA glass lenses that provide extremely low chromatic dispersion and a bright, sharp image."
