The hitech 150x150mm 6x6 inch irnd prostop 1 stop 03 filter produces a grey neutral effect and is used to reduce light in photography enabling more control over exposure and depth of field without affecting colour balance or contrast the filter is made from the highest quality 15mm optical resin and is designed to reduce the amount of light reaching the sensor by 1 fstop allowing you to get creative with long exposures the effects created by using a slower shutter speed is motion blur