The Singh-Ray 77mm George Lepp 0.9 Neutral Density Thin Mount Filter is a solid ND filter that provides a 3-stop reduction in exposure. This 0.9 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.
Singh-Ray ring-mounted filters are constructed from highly polished glass and specially formulated optical laminates. The thin ring mount design measures 4.6mm-thick and helps to prevent vignetting when used on wide-angle lenses. They do not feature front threads for stacking filters or using clip-on style lens caps.