UV lens is also called UV ultraviolet filter, namely UltraViolet. Usually it is colorless and transparent. But because of some added anti-reflective coating, it looks like purple or purplish red from certain angle. Many people buy UV lens to protect the delicate lens coating. In fact, this is only a subsidiary function of it. The main function of the UV is for absorbing ultraviolet with wavelength below 400nm, but there were no filtering effect on other visible / invisible light. The reason why it is able to filter UV is because the lens contains lead. Therefore UV filter is heavier than lens with the same size and the thickness
CPL polarizer role: polarizer can eliminate harmful reflected light and improve image's clarity and expression. Eliminating reflected light: eliminate reflected light from the surface of water or glass, etc.. Increase color saturation: to make the blue sky, green leaves, ridges and construction, and other colors more vivid. Circular polarized CPL is specially used for AF focus camera and digital camera, the rotation adjustment is more convenient. In addition, it is also compatible with MF manual body.
FLD fluorescence filter: designed for eliminating neon lights, "warm white fluorescent light and green reflection light, clear the deep blue on photos. When using, should avoid photography directly facing the light source. Fluorescent mirror is a kind of special color compensating filter. Under fluorescent lighting shooting using daylight color photos, the screen will appear blue and green, but if you join a fluorescence filter lens (Ying Guangjing). The phenomenon, partial color can be correct, so that the screen color can be restored. The fluorescent mirror provides the correct color, eliminating the bad color of the green fluorescent light bulbs. The fluorescent mirror is actually designed to convert fluorescent light. It provides proper skin color and natural color under fluorescent light. It is the color of magenta, adding warmth to the overall correct color, eliminate bias caused by poor projection of green fluorescent lamp.
