The Hoya Variable ND Filter uses two polarization layers to control the amount of light that passes through the filter and into the camera lens. At its lowest setting, the filter allows one-third of the light to pass through, equivalent to 1.5 stops or shutter speed values. At its maximum, the filter only lets through 1/400th of the light, corresponding to 9 stops or shutter speed values.

Once the filter is mounted on the lens, rotating the filter ring between "Min" and "Max" allows for optimal control of the amount of light entering the lens. With the Hoya variable ND filter, it is possible to take photos with fast lenses, such as a 50mm f/1.4, at wide open aperture in full sunlight to achieve a very shallow depth of field. Alternatively, the shutter speed can be slowed down to achieve exposure times of several seconds in bright sunlight. This longer exposure time allows for motion blur effects to be created. The popular effect of flowing water appearing almost like mist is thus achievable. Almost any moving object can create a great impression of movement.

For video content creators, ND filters are very helpful in adjusting shutter speeds to match the frame rate while maintaining the depth of field of the footage.

The Hoya ND variable filter uses high-quality optical lenses from Hoya Corporation, the world's largest manufacturer of optical glass. It is available in diameters ranging from 52mm to 82mm. For best results, it is recommended to use a tripod when shooting with long exposure times.