Schneider ND 1,2 Attenuator Horizontal 4 x 5.65. This is a special type of Neutral Density Filter. Neutral Denisty Attenuators diminish distracting backgrounds by enabling the use of wider lens apertures, thereby reducing depth of field. Conversely, these ND Attenuators can be used to properly expose varying light levles within a given frame. They allow the amount light reaching the film to be controlled without relying solely on camera aperture. Neutral Density Attenuators are made using the finest crystal-clear water-white optical glass and are precision engineered with unparalleled smoothness, uniformity and consistency. They can be used alone or in combination with other filters with no degradation of image quality.