K&F Concept 4 x 5.65 inch ND0.9 (3-Stop) Cinema Filter

This square cinema filter from K&F Concept in 4 x 5.65 inch format is designed for video productions that work with matte boxes and need fixed and predictable light reduction. Its density ND0.9 is equivalent to 3 stops of reduction, enough to maintain more natural shutter speeds outdoors or under intense lighting without aggressively altering the exposure.

The product sheet indicates HD optical glass construction with polishing on both sides, ultra-slim design and 28 layers of multi-layer coating. K&F also claims an ultra-low reflectivity of 0.2%, aimed at reducing internal reflections and flare when working with studio lighting or backlights, while maintaining better contrast and cleaner highlights in HDR or log streams. The format is designed to fit Tilta matte boxes, SmallRig and other systems compatible with 4 x 5.65 filters.

It's a logical choice for filmmakers, commercial videographers and small teams who already use matte boxes and want to add a fixed 3-stop ND to their set. It also makes sense as a base piece for interviews, controlled daytime exteriors and sequences where it is advisable to preserve motion blur without resorting to variable solutions.