As we all know, neutral density filter is also called ND filter. ND filter reduce the amount of light passing through the camera’s imaging sensor. It modifies the intensity of color, all the wavelength and light equally but not affect the original color.

ND filters are usually used in wider apertures. This can be used to decrease the depth of filed. This would allow the centered info to be separated from the background.

The filter is usually used in photograph or other optical system combination. In general, size could be Dia 46mm, 49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm, 86mm.

ND number notation

Fraction of whole lens

Optical density value

F-stop reduction

Transmittance

1

0.0

100%

ND2

1/2

0.3

1

50%

ND4

1/4

0.6

2

25%

ND8

1/8

0.9

3

12.5%

ND16

1/16

1.2

4

6.25%

ND32

1/32

1.5

5

3.13%

ND64

1/64

1.8

6

1.56%

ND128

1/128

2.1

7

0.78%

ND256

1/256

2.4

8

0.39%

ND512

1/512

2.7

9

0.20%

ND1024

1/2014

3.0

10

0.098%

ND2048

1/2048

3.3

11

0.049%

ND4098

1/4098

3.6

12

0.024%

ND8192

1/8192

3.9

13

0.012%