
A neutral density (ND) filter reduces the amount of light that enters the lens. ND8 is equivalent to three stops.
Usually, there is a shortage of light in photography, but sometimes there can be too much. In bright sunlight, using a large aperture can be impossible without an ND filter. A neutral density filter is also needed when you want to photograph, for example, flowing water in bright weather and with a really long exposure time.
This filter also features IR filtering to reduce color distortion caused by infrared rays. The multi-layer coating reduces reflections.
The aluminum frame is thin, so vignetting is minimal even with ultra-wide-angle lenses.