What Is a Neutral Density Filter in Photography?

A filter used in front of the lens that absorbs all visible wavelengths and significantly reduces the amount of light that reaches the sensor. Neutral density filters are particularly useful in situations where excess ambient light does not allow you to use the shutter speed and aperture you require to achieve a desired photographic effect. One example would be photographing daytime seascapes where you wish to use a long exposure time to allow blurring of the water to create a sense of dynamic movement.

 

F-Stop ReductionOptical DensityFilter Factor% transmittance
000100
10.3250
20.6425
30.9812.5
41.2166.25
51.5323.125
61.8641.5625
72.11280.78125
82.42560.390625
92.75120.1953125
103.01024 (sometimes called ND1000)0.09765625
113.320480.048828125
123.640960.0244140625
133.981920.01220703125
13 1/34.0100000.01
144.2163840.006103515625
154.5327680.003051757813
164.8655360.001525878906
16 2/35.01000000.001
175.11310720.0007629394531
185.42621440.0003814697266
195.75242880.0001907348633
20610485760.00009536743164