The ND Filters Set includes ND4, ND8, ND16, and ND32. These high-quality, light-reducing ND filters provide advanced users with precise control over shutter speed, and ensure clean footage even when the shutter opens to 180° with low ISO during recording. Made of high-quality light reduction materials, this filters set helps you capture true colors and stunning highlight and low-light details. A precise snap-joint design ensures a reliable fit and lens seal during flight. Shutter opening angle is a common way of describing the shutter speed relative to the frame rate. For example, if the camera is recording at 24 fps with the shutter open at 180°, the exposure time is 1/48 second.