Natural Night Filter 77mm. All the NiSi quality in one filter. Like the entire range of NiSi optical glass, the Natural Night Filter is part of a high-quality manufacturing process. Its surface treatment ensures sharpness for all cameras with the most demanding sensors available on the market. It features NISi's unique Nano Coating technology: this multi-layer coating reduces surface reflection and ensures clear sharpness. It also has a water-repellent coating on both sides, which simplifies maintenance.