ND Filters' main role is to reduce the amount of light when the light is too bright so that the camera can choose the correct exposure value to avoid overexposure. It can also "resist" a large number of scattered light, can improve the color saturation of the picture, make the picture more transparent gorgeous. The use of a ND filter can also use a slower shutter speed to shoot some special effects, such as fog-like water, light tracks at night, and so on. When shooting video under the hot sun, the shutter speed can be reduced by using the dimmer filters, so that the video picture has the appropriate motion blur and looks more comfortable.