Calcium fluoride lenses can also be fluorite lens. Fluorite is made of CaF2 crystal. Its obvious characteristics are low refractive index and dispersion, good transmittance for infrared ray and ultraviolet ray. The bigger concern is it has colorful and exquisite description performance while general optical glass can not achieve.Because light ray which gets through general lens will give away and reduce the acuity of image, we call it chromatic aberration. Fluorite lens suits taking lens best because of its little dispersion without chromatic aberration. Through adopting fluorite lens with low refractivity, it can drastically shorten the length of telephoto lens with high quality image.
The material of fluorite lens is fluorite, its main ingredient is CaF2 with much impurity. Natural fluorite is always with vivid color, its hardness is lower than knife. Fluorite is a kind of good optical material, lens that made of fluorite is with excellent optical quality, especially in the aspect of dispersion resistance, it is better than all other optical material.