The NiSi 72mm ND-VARIO Pro Nano 5-9 stops (ND 1.5 – 2.7) Enhanced Variable ND is a variable neutral density filter providing an exposure reduction of 5 to 9 stops. The degree of density is easily controlled by rotating the silver knob. The transition of density occurs smoothly which allows the photographer or videographer to adjust exposure length to the exact amount required for a given scene. Providing a reduction of 5 to 9 stops, this filter allows you to control depth of field and convey movement more easily. This reduction offers increased flexibility to use specific ISO settings or ISO films under bright ambient light and provides increased exposure flexibility while using cinema or video cameras within a designated film frame rate.Each glass surface includes nano-coating that helps to prevent reflections, glare and repel water and dust.Please note the front filter thread of this filter is 77mm and is larger to avoid vignetting on wider lenses.