The Neutral Density x400 (ND) 2.7 Hoya Multi-Coated (HMC) Glass filter from Hoya has several uses and offers the possibility to achieve otherwise unachievable results. ND filters appear grey and reduce the amount of light reaching the film. They have no effect on color balance. Multi-coated to minimize reflection at the filter surfaces which reduces flare and ghosting.
Photographing solar eclipses and ultra-bright light sources can be extremely dangerous. This filter reduces light values by 9 stops to less than 1/500th of its original intensity and allows safe photography. It can also be used to achieve super slow shutter speeds in daylight to render moving subjects invisible.
Neutral Density filters Have Four Main Uses
To enable slow shutter speeds to be used, especially with high speed ISOs, to record movement in subjects such as waterfalls, clouds, or cars
To decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background
To decrease the effective ISO of high speed ISOs (above ISO 400) and allow it to be used outdoors in bright situations
To allow cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which could cause overexposure