A neutral density filter reduces the light entering the lens.
Use a longer exposure or wider aperture when the scene would otherwise be too bright.
ND strength is often described in stops. Reducing incoming light allows a compensating change in shutter time or aperture.
Use an ND filter to explore deliberately blurred moving water in daylight.
Match the filter to the lens diameter and check for darkened corners, especially when stacking filters.
Follow a connection to understand how these ideas fit together.
An ND filter reduces incoming light.
Reduced incoming light permits a longer shutter time for comparable exposure.
An ND filter can permit a wide aperture in a bright scene.
A longer exposure made possible by ND can deliberately show subject movement.
Source check: . This records a check of the supporting references; it is not an expert endorsement.
ND strength is often described in stops. Reducing incoming light allows a compensating change in shutter time or aperture.