Before revision: Borosilicate crown glasses such as BK7 ( = 1.51680 , = 64.17 , D = 2.51 g/cm³), which is commonly used in telescopes and binoculars, and fluorite crown glasses such as the best optical quality low dispersion glass currently in production, N-FK58 made by the German company Schott with the following characteristics ( = 1.456 , = 90.90 , D = 3.65 g/cm³) and are commonly used in high-end camera lenses).
After revision: Borosilicate crown glasses such as BK7 which is commonly used in telescopes and binoculars, and fluorite crown glasses such as the best optical quality low dispersion glass currently in production, N-FK58 made by the German company Schott with the following characteristics and are commonly used in high-end camera lenses).