Linear Variable ND Filters: BK-7 (375nm to 2000nm)

The linear variable neutral density filter (ND Filter) is used to attenuate light as the filter is translated. The filters can be used with white light as well as with low power lasers. A large finite aperture can be attenuated by translating two filters in opposite directions. The filters are available in lengths from 5mm to over 200mm. These ND filters are more sensitive to position at lower density values than are linear transmission filters. The useable wavelength range is from 375nm to 2000nm.