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Neutral Density Filters

Neutral density filters are used to attenuate the intensity of an incident light beam, even over a wider spectral range.

The neutral density filters available from Eureca are based on a correspondingly applied metal coating on glass substrates.

Such filters are used, for example

  • as a test option for the absorption accuracy of photometers,
  • to increase exposure times,
  • for reducing the amount of light emanating from illuminations.

The filters are available in various standard sizes and some commonly used mounts. Other customized sizes and the delivery of the filters in plug-in or screw mounts are also possible. Please contact us if you need help.

Designation Optical density Thickness [mm]
ND-0.05-x 0.05 0.7
ND-0.1-x 0.1 0.3
ND-0.15-x 0.15 0.7
ND-0.2-x 0.2 0.3
ND-0.3-x 0.3 0.3
ND-0.5-x 0.5 0.3
ND-0.8-x 0.8 0.3
ND-1.0-x 1.0 0.3
ND-1.2-x 1.2 0.3
ND-1.6-x 1.6 0.3
ND-2.0-x 2.0 0.3
ND-2.3-x 2.3 0.3
ND-2.7-x 2.7 0.3
ND-3.0-x 3.0 0.3

When placing a request or order, please replace the »x« in the table above by the order code for the size needed:

Order code Size or Mount Clear aperture
15 15.0mm round ≥ 12mm round
25 25.0mm round ≥ 22mm round
50 50.0mm round ≥ 49mm round
50x50 50.0x50.0mm square ≥ 49x49mm square
C-Mount C-Mount 25mm ≥ 21mm round
M25.5x0.5 M25.5x0.5 ≥ 21.9mm round
M27.5x0.5 M27.5x0.5 ≥ 22.3mm round
M30x0.5 M30x0.5 ≥ 26.5mm round
M35.5x0.5 M35.5x0.5 ≥ 32.1mm round
M37x0.5 M37x0.5 ≥ 33.2mm round
M39x0.5 M39x0.5 ≥ 35.1mm round
M40.5x0.5 M40.5x0.5 ≥ 36.2mm round
M43x0.75 M43x0.75 ≥ 39.4mm round
M46x0.75 M46x0.75 ≥ 42.3mm round
M49x0.75 M49x0.75 ≥ 45.2mm round
M52x0.75 M52x0.75 ≥ 48.0mm round

Example: ND-0.05-25 is the correct order designation for the first filter of the table with a size of 25.0mm round.


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Last update: 2019-14-07