The cokin x pro series 154 neutral density filter is a solid neutral grey filter providing an exposure reduction of about 3 stops this 09 density creates a darkening of the entire image allowing you to photograph with a wider aperture or slower shutter speed than normally required by slowing your exposure time or increasing your aperture you are able to control depth of field and convey movement more easily neutral density filters do not affect the coloration of the image and are ideal for