The LEE85 Big Stopper from LEE Filters is an 85 x 85mm long exposure neutral density filter that reduces the amount of light entering through your lens by approximately ten stops. This solid 3.0 density filter darkens the entire image to permit photographing with a slower shutter speed or wider aperture than normally required. By increasing aperture width or your exposure time, you can control depth of field more easily or make anything that is moving in the image - such as clouds, waterfalls, people, or traffic - appear blurred or ghostlike to convey movement. The LEE85 Big Stopper is constructed from high quality optical glass for clarity and high definition. It is designed for use with compact cameras, mirrorless cameras, and mirrorless lenses. Use the Big Stopper with other LEE filters and maintain the slot in the LEE85 filter holder nearest the lens free for the Big Stopper. A tin is supplied with the filter for storage and transportation.