"Specifically made for the Zenmuse X4S, this ND filter reduces the amount of light coming into the sensor. It gives you the freedom to create your own work by allowing more control of the camera's aperture, exposure time and sensor sensitivity settings. Put more simply, the ND filter helps avoid overexposed photos. The ND16 filter allows 1/16 of incoming light through, equal to a 4-stop filter. Reduces light by 2 stops to effectively avoid over exposure, so that you can capture great photos in a wider range of environments."