Colored optical filter

glassabsorptionneutral-density

Glass Neutral Density filters attenuate light by absorption just like the gelatine neutral density filters. Glass ND Filters are more robust and tend to have more uniform absorption characteristics. They also attenuate by absorption and so care must be taken to avoid overheating. Attenuation is achieved by polishing standard schott NG or equivalent glasses to a given thickness. The filters listed here are a range of mounted absorption 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 absorption ND 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 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.