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Knight Optical(UK) Ltd - - +44 (0)1622 859444

Mounted metallic neutral density filters

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This product is in development. We already supply a range of custom mounted filter solutions to customers worldwide.

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Metallic neutral density filters comprise a thin metallic layer on a borosilicate or equivalent glass or UV grade fused silica polished window.  Metallic ND filters attenuate the light by reflection and thus avoid the possible heating issues with glass and gelatine neutral density filter types. However care must be taken to ensure the reflected light does not cause problems.  Our stock range of visible/IR range of metallic neutral density filters are coated on low-expansion borosilicate or equivalent  glass substrates and cover the range from 350-2500nm. Our UV range of metallic neutral density filters are coated on UV grade fused silica and therefore cover the useful UV region down to 170nm.

All metallic ND filters are supplied with a copy of the spectral transmittance scan taken on a filter at the time of the production coating.  We stock uncoated borosilicate or equivalent and UV fused silica substrates so custom metallic filters can be supplied to your specific request, please enquire.

The filters listed here are a range of mounted metallic  neutral  density filters.  There are two options of 25.5 and 30.5mm x 0.5mm thread sized mounts that both fit standard 25mm diameter filters with a 22mm dia clear aperture.

These mounts have male threads with 0.5mm pitch threads and are designed to fit standard fixed focused and megapixel lenses.  These mounted filters for example screw directly onto Tamron, Fujinon and Sony lenses which have a 25.5 thread on the front.

These mounted metallic  neutral  density filters allow for easier integration and alignment in optical systems as well as safer changing of filters in systems that require switching between alternative optical density values.

A wide range of unmounted metallic and absorption neutral density filters are available from stock in 12.5mmdia, 25mm dia and 50x50mm squares, all stocked as individual filters.  For ease, view the “see also” tab for selection of these filters and other types of neutral density filters including convenient sets.

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