ND04B Dia. 25 mm Unmounted Reflective ND Filter; Optical Density 0.4

The ND04B is a circular Neutral Density Filter with a diameter of 25 mm and a thickness of 1 mm, sourced from the renowned optical component vendor, Thorlabs. This filter is designed to reduce the intensity of incident light without altering its color composition, making it an essential tool for various optical applications.

The filter's Neutral Density (ND) coating, denoted as 'tho nd04' on both the front and back surfaces, boasts an Optical Density (OD) of 0.4. This specific OD value signifies that the filter reduces the light intensity by a factor of 1.6, providing a subtle yet effective light reduction.

The ND04B filter is crafted from N-BK7 Schott, a high-quality borosilicate glass known for its excellent optical properties, including low auto-fluorescence, high homogeneity, and excellent transmission in the visible spectrum. This material ensures the filter's reliability and performance in various optical systems.

The filter's thin lens shape allows it to be easily integrated into various optical setups, while its unmounted design provides users with the flexibility to pair it with their preferred mounting solution. The ND04B filter's availability and in-stock status further emphasize its practicality and accessibility for users in need of a dependable Neutral Density Filter.