Explain the function, usage and other related aspects of SLR starlight glasses, the more the better.

Starlight mirror is a kind of camera filter, which is used to realize the beautiful starry sky canopy effect. After using the starlight mirror, the point light source in the picture will emit beautiful stars, which can bring a dreamy and romantic effect to the whole picture. Often used in wedding photography and night scene shooting. Its principle is that a series of parallel lines are etched regularly on the surface of colorless optical glass to produce the radiation effect after light diffraction. There are 2 lines, 4 lines, 6 lines, 8 lines, 16 lines and so on.