Neutral Density (ND) filters are the most requested and essential photographic filters for several reasons. For photographers, an ND filter means precise control over the amount of light entering the lens for greater creative control over exposure. For video content creators, ND filters greatly help adjust shutter speeds to match the frame rate while maintaining the depth of field of the footage.

Among the varieties of ND filters, ranging from ND2 to ND1000, or even ND100000, ND filters can generally be categorized into 3 basic groups:
Low density filters (ND2 – ND8)Medium density filters (ND16 – ND200)High density filters (ND500 – ND1000/ND100000)
Low density filters will reduce the shutter speed on a sunny day to allow you to reduce the depth of field in very bright light or to use a wider aperture to stay below the diffraction limit. For example, these filters are necessary for shooting with your fast lenses like F1.4 or F1.2 at maximum aperture for smoother and more beautiful bokeh.

Medium density filters will help you add motion blur to the subject in conditions that would generally not allow the camera's shutter speed to do so.

If you are looking for more creative shots based on extremely slow shutter speeds, high density filters are recommended. ND filters like ND500 or ND1000 will help capture an unreal fantasy world that cannot be seen by the human eye.

Solution to the color shift problem
HOYA offers its own exclusive and extensive range of ND filters, marketed under the PROND EX series, for photographers and filmmakers. PROND EX filters adopt HOYA's clear optical glass, mounted in a lightweight and precisely machined aluminum frame. The frame has front threads allowing for the attachment of additional filters or a lens cap.

Thanks to ACCU-ND technology, which places HOYA ND filters well ahead of other brands, the image suffers no negative color shift effects that can occur due to poor quality materials, poor manufacturing quality control, or issues with infrared spectrum light leakage. The latter problem is the most significant nowadays in photography and videography.

HOYA's exclusive ACCU-ND technology allows for equal light reduction across both the visible and infrared spectra. Consequently, the photographer does not have to worry about color shift issues when using HOYA ND filters in different shooting conditions.

PROND filters in video production
ND filters are also an irreplaceable tool in video shooting. For example, when shooting with a Sony camera in Slog mode, the ISO cannot be set below 800. To achieve natural motion, it is recommended to adjust the shutter speed to the frame rate setting. During the day, PROND EX 8, PROND EX 64, PROND EX 1000, or their combination (such as PROND EX 8 + PROND EX 64) would be necessary to achieve cinematic quality.

PROND filter combinations
The choice of ND filters depends on the photographer's intentions to achieve the desired effect in the image. If the effect obtained with a single ND filter does not satisfy the photographer's vision, combining PROND EX filters can also be useful. For example, the combination of PROND EX 8 + PROND EX 64 will give an effect equivalent to an ND500 filter, which can be used to express an unreal fantasy world. The combination of PROND EX 8 + PROND EX 1000 will give an effect equivalent to an ND8000, which will allow for capturing the surface of the Sun without overexposure with solid color and the visibility of black spots.