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, which corresponds to 1.5 stops or shutter speed values. At its maximum, the filter only lets through 1/400 of the light, equating 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 pictures 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. The longer shutter speed can create motion blur effects, making it possible to achieve the popular effect where flowing water appears almost like mist. Almost any moving object can create a great impression of motion this way.

For content creators, ND filters are very helpful in setting 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.