In this video, I demo why you need to use a neutral density filter when making videos. The filters used in this demo was the Freewell Variable ND Filter.
ND filters are used to help reduce your shutter speed in order to follow the 180-degree rule while maintaining proper exposure. The 180 degree refers to the shutter angle used with film cameras, a 180-degree shutter will equal to double the frame rate. If you’re filming at 24fps, your shutter should be at 1/48. Without following the 180-degree rule, your footage could end up looking jittery, edgy and unnatural.
Shooting at 1/48 or 1/50 with a wide open aperture on a sunny day is next to impossible. That’s where the ND filters come in. The filter reduces the level of light entering the lens so you can maintain the proper shutter speed for natural looking videos.