One half of this filter is NDx4 Neutral Density and the other half is clear, with a soft boundary between the two. It is used to control bright/dark contrast, by reducing half the shot by 2 stops.
Particularly useful in landscape photography, the rotating mount allows bright skies to be easily controlled for dramatic effect.
Reviewed by 2 customers
when depth of field and creativeness is critical, the ND split filter delivers the end result.
Like all split neutral density filters you need a reasonably level horizon,otherwise you will be darkening items that should remain unaffected. Also,if using your camera's autofocus,you need to make sure that the filter's dividing line is horizontal when you get ready to shoot. With these caveats in mind, the filter will perform like a champ.