The Hoya Variable Density II is a filter with adjustable density and an ND range of 1.5 to 9 stops (ND3-400). The filter features a newly designed rotating frame with a convenient dial for better operation. For still images, variable density filters shorten the shutter speed according to the photographer's intentions when the shutter speed cannot be reduced due to camera limitations. In video recordings, it is important that the shutter speed corresponds to the set frame rate. This means it should ideally be double the frame rate for optimal results. By using variable density filters, the shutter speed can be adjusted to the correct value to achieve the natural and smooth motion desired in video recordings.