K&F Concept Nano-X 2-in-1 Variable ND4–ND64 and CPL Filter, 40.5 mm

Nano-X — variable ND filter 40.5 mm, changes the amount of light steplessly as you turn it.

• 28 anti-reflective layers, reflectance 0.2 %
• Screws onto a lens with a 40.5 mm thread.
• The surface repels water and grease and resists scratches
• ND range: ND4 – ND64 (2–6 stops)
• Optical glass
• Aluminium alloy with end stops

A variable ND replaces a whole set of fixed grey filters — turning the front ring changes how much light gets through, steplessly. While filming the shutter stays at 1/50 s even as the sun goes behind a cloud and comes back, with no need to stop the take or swap a filter.

28 layers against flare

The glass carries 28 anti-reflective layers and reflects only 0.2 % of the light, so no ghosting or veiling appears against the light.

Water and grease roll off

The surface repels water and grease, so drops run off and fingerprints wipe away without smears; the coating also stands up to cleaning in the field.

ND and polarisation at once

Two functions in one piece of glass: the variable ND cuts two to six stops and the polarising layer also takes the glare off water and glass. One filter sits on the lens instead of two stacked, so there are no extra reflective surfaces and no added risk of dark corners.