The cokin a series ba 400 filter holder is adaptable to all lenses and comprises a complete range of cokin filters for lenses with diameters from 36mm up to 62mm this filter holder includes a wide range of adapter rings as well as numerous dedicated accessories it is recommended for focal lengths 35mm onwards 35mm format the a filter holder allows up to three filters to be used to create a unique effect and is the smallest cokin slot in system available with an adaptor ring fix the filter