The Cokin A121F filter has a gray gradient over its entire surface, from ND8 at the top edge to ND2 at the bottom. It is used most often when we want to align exposure or highlight some part of the frame. Cokin filters are mounted with the help of a holder (holder), which is attached to replaceable mounting adapters, with diameters that can be adapted to your lens. System A (size S) is recommended for use with compact cameras with lens filters or amateur video cameras.