In conditions of extreme light intensity, such as sunshine on snowy mountains or on the beach, or when using a camcorder, Neutral Density filters are recommended as essential. Neutral Density filters are often ignored by photographers, but they have several uses and offer the possibility to achieve otherwise unachievable results. Neutral Density filters appear grey and reduce the amount of light reaching the film or imaging sensor, they have no affect on color balance.
The primary benefits of using a Neutral Density Filter include:
+ Allows the use of slow shutter speeds, especially with high iso's, to record movement in subjects such as waterfalls, clouds, or cars
+ Decreases the depth of field so that wider apertures can be used, which helps separate subjects from their background
+ Decreases the effective ISO of high speed film which allows it to be used outdoors in bright situations
+ Reduces the exposure when using cine and video cameras with fixed shutter speeds so that subjects such as snow, sand or other bright scenes can be filmed which otherwise might be overexposed
ProMaster Digital HD Neutral Density filters are made from premium optical glass, have 12 layers of coating to reduce reflected light and feature a super slim 4.5mm frame that avoids vignetting on extra wide lens focal lengths.
The ProMaster Digital HD ND4X has a factor of .6 which reduces light by 2 stops and has the effect of reducing the ISO to 1/4 of rating.