A neutral density filter is a black filter used to reduce the amount of light taken in by the lens. ND is an abbreviation for inch Neutral Density inch and means inch neutral concentration inch . ND filters reduce the amount of light without affecting the color. With an ND filter you can control the shutter speed and aperture and you can create creative expressions that can only be done with an optical filter. Use an ND filter when you want to intentionally slow down the shutter speed to capture the fluidity of the subject.
Marumi filters are made in Japan and feature a water and oil repellent coating