Who can talk about fluorite lenses?

Sure! Fluorite is a kind of calcium fluoride crystal with extremely low dispersion, and its ability to control chromatic aberration is better than that of UD lens. Strictly speaking, fluorite is not glass, but crystal. Its refractive index is very low (1.4) and it is not affected by humidity. Generally speaking, fluorite lenses are not exposed, so you are unlikely to touch them directly. Although fluorite lens is not as impact-resistant as ordinary glass, it is not as fragile as expected, so it does not need special care in use. At present, the main manufacturer of fluorite lenses is Canon of Japan, and many of its high-end lenses use fluorite lenses.

Adopt it