In principle, these filters reduce the total amount of light reaching the camera sensor. This allows photographers to work with larger apertures or slower shutter speeds. The whole filter is neutral grey in colour and does not affect the colour balance of the scene being photographed. In order to select the correct filter to match the light level, Cokin ND filters are available in various densities: light, medium and dark with exposure factors of 2x, 4x and 8x or 1, 2 and 3 stops (These are also sometimes known as 0.3ND, 0.6ND and 0.9ND).
Filter Size: 84 x 84mm
Filter Material: CR39 Organic Glass