Description: A Neutral Density Filter or ND filter is a filter that reduces or modifies the intensity of all wavelengths or colors of light equally, giving no changes in the hue of color rendition. The purpose of a standard photographic neutral density filter is to reduce the amount of light entering the lens. Doing so allows the photographer to select combinations of aperture, exposure time, and sensor sensitivity that would otherwise produce overexposed pictures. This is done to achieve effects such as a shallower depth of field and/or motion blur of a subject in a wider range of situations and atmospheric conditions. Feature: --Ideal for reducing bright light in large aperture situations when a narrow depth is field is needed. --Allows for slower shutter speeds when blurring or showing of movement is desired. --Allows balancing of exposure to highlight a key subject. --Lets you use higher speed films in bright light. --Easy to transition between different lenses by using a matte box when your camera is sitting on the rig. You can just simply pull out the matte box filter holder and pop in this 4x 4filter for different size lenses. Material: High-quality optical glass with coating Size: 4x4(100 mm x 100 mm) (2mm thick) Suitable for: Standard matte box Package Includes: 1pcs of 4x4Full ND4 filter for mattebox