ND filters reduce evenly the transmittance of light over the entire VIS spectrum. They decrease the brightness of an image without
changing the depth of field (DoF).
They attenuate light by absorbing a part of the energy of the VIS wavelength, without influence
on the color balance. ND filters are used to control the intensity of light going through an optical system to avoid overexposure, blooming on imaging sensors and prevent damages on light sensitive measuring sensors.
ND filters are available mounted with common thread sizes M 25.5 to M 67 and unmounted in sizes 27 mm to 74 mm diameter. Intermediate size down to 10 mm possible on request.