NiSi NIR-PR-40 40mm HUC UV Protection Filter

The NiSi NIR-PR-40 is a 40mm UV and protection filter built with high-definition optical glass and double-sided nano coating. With a measured light transmission of 99.3%, it sits on the front of a lens and provides a physical barrier against dust, moisture, scratches, and accidental impacts without meaningfully affecting the light reaching the sensor. The nano coating serves multiple functions: it creates a hydrophobic surface that causes water to bead and roll away, adds scratch resistance to the glass surface, reduces reflections that could cause flare or ghosting, and makes the filter far easier to clean in the field. Both sides of the glass receive this coating for consistent performance.

The frame is machined from high-quality aluminum with a total thickness of just 5.2mm, making it one of the thinner protection filters available for the 40mm thread size. This slim profile is engineered to avoid vignetting on wide-angle lenses, where thicker filter frames can intrude into the corners of the image. The outer edge features superfine dull polishing and elaborate knurling, giving photographers a secure grip when threading the filter on or off — a small but practical detail, especially when working quickly or in less-than-ideal conditions. For photographers using compact cameras, mirrorless bodies with small primes, or specialty lenses with a 40mm filter thread, the NiSi HUC Protector provides reliable, optically transparent front-element protection.