Cokin diffusers have very little effect on the sharpness of the image they merely diffuse highlights thus reducing contrast as such diffusers can be used to soften a landscape or soften skin texture in a portrait to hide minor flaws cokin diffusers are available in three grades 1 083 2 084 and 3 085 with 3 having the greatest effect this filter measures 85 x 85mm and fits the cokin p series holder maintains sharpness diffuses highlights high quality cr39 resin