Hoya variable neutral density filter providing an exposure reduction of about 1.5 to 9 stops. The 0.45 to 2.7 density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than would normally be required. The degree of density is easily controlled by rotating the front filter ring, helping you to predetermine the additional exposure length required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily.
Variable neutral density filter allows you to dial in differing amounts of density from scene to scene
0.45 to 2.7 density filter darkens the image, allowing you to photograph with a longer shutter speed or wider aperture than normally required
Providing a reduction of 1.5 to 9 stops, this filter allows you to control depth of field and convey movement more easily
Offers increased flexibility to use specific ISO settings or ISO films under bright ambient light
Provides increased exposure flexibility while using cinema or video cameras within a designated film frame rate
Slim profile filter ring helps to reduce the likelihood of vignetting with wide-angle lenses
An example: The if your normal exposure without the filter is 1/250 of a second at f/11 the and you mount the filter and set it to the Min setting, then your exposure will be 1/90 of a second at the same f/11 or it could be 1/250 of a second a f/6.5 depending on which setting you want to control. If your desired effect is motion blur in the picture then turn the filter ring and watch your shutter speed drop in camera. At Max setting a shutter speed of 2 full seconds (9 stops) is possible at the same f/11 aperture.
This is an especially useful tool when creating motion blur in moving water such as waterfalls, rivers and crashing waves. Other examples of good times to use very slow shutter speeds to create blur are; moving vehicles, trains, cars and congested city traffic; blurred panning effects where the subject, a runner, bicyclist or car is clear but the background around it is blurred from the camera following its movement
Variable Neutral Density filters, and ND filters in general have these main uses:
Slow down shutter speed for motion blurring effects like waterfalls, cars or blurred panning movement to make the subject stand out from the background.
Allow wider apertures to be used to decrease depth-of-field, literally focusing more attention on the subject.
Allow higher ISO films to be used in brighter lighting conditions
Allow cine/video cameras, which have a fixed shutter-speed range, to film on brighter lighting conditions such as the beach or in snow on a sunny day.
The Hoya Variable Density filter uses high-quality optical glass from Hoya Corporation, the worlds largest optical glass manufacturer and is available in sizes 52mm to 82mm.
For best results Hoya recommends using a tripod when photographing with slow shutter speeds.
Notes:
The practical exposure range and light transmittance will vary depending on the situation. When using the filter near or at MIN a cross-like dark pattern will appear across the image and cannot be eliminated. This is a property of the filter and all variable ND filters.
Hoya official product link : http://www.hoyafilter.com/hoya/products/ndfilters/variabledensityfilter/
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