K&F 100MM Handheld Spiral Filter Optical Glass Prism Special Effect Camera Lens Filter Nano-Basic Series

Nano-B — spiral halo filter, wraps the lights in a swirled veil.

• Held in the hand in front of the lens, the position of the effect can be changed during the take
• K9 optical glass, aviation-aluminium frame with a handle

A spiral is ground into the glass, wrapping bright areas in a swirled veil and softly smearing the edges of the frame. The centre stays sharp, so the main subject holds and the blur works only around it. Turning the filter changes the way the veil curls.

The filter does not screw onto a thread — it has an aluminium handle and is held freely in front of the lens. That lets you steer exactly where the border between the clean and the swirled part of the frame runs, and while filming it can be shifted by hand during the take.

The effect is spiral: one part of the frame stays sharp, the other winds into a veil with the light curling around it. The K9 glass keeps the drawing clean, so the sharp part really is sharp.