It can prevent accidental damage to the lens, and it can also avoid accidentally touching the lens with your fingers. When shooting in front and in the side, you can avoid the surrounding scattered light from entering the lens. In light photography or night photography, you can avoid the interference of light from around the lens. In backlight, side light or flash photography, can prevent the entry of non-imaging light, to avoid fog. It can also cover the sand, rain and snow for the camera to some extent.