This ND plain filter reduces the amount of light reaching the film, but without affecting the colour balance. Equivelant to a 1 stop Shutter speedAperture decrease.
Without altering colours, the Cokin P153 NDX4 Neutral Density Filter corresponds to a loss of light equivalent to two stops, allowing you to gain the 2 apertures you need to allow you to play with backgrounds, distance and depth of field, or to use a...