This Cokin filter kit includes a filter holder, Grad Grey ND2 (121L Light), Grad Grey ND4 (121M Medium) and Grad Grey ND8 (121S Soft) filters. These gradual neutral grey filters reduce the total amount of light reaching the film without affecting the colour balance.
Each filter is clear at the bottom half with a gradual transition of the ND effect in the top half of the filter. They produce a grey neutral tone and are used to reduce light, enabling more control over the exposure and depth of field. For example, when photographing landscapes in which the sky is much brighter than the foreground, placing the neutral density part of the filter onto the sky in the frame will reduce the sky exposure without affecting the foreground.
This kit is recommended for focal lengths from 20mm onwards (35mm format) and anything wider than 20mm will show the edge of your holder in the frame. Note: No adapter rings are included and are available separately