K&F Concept C Series variable ND filter ND2–ND32 + CPL 2-in-1 82 mm

C Series — variable ND filter 82 mm, changes the amount of light steplessly as you turn it. It is a favourite for filming on bright days, as it lets you keep a cinematic shutter and a wide aperture without blown highlights or swapping filters between takes.

• Screws onto a lens with an 82 mm thread.
• The surface repels water and grease and resists scratches

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. 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.

The filter combines two pieces of glass that otherwise have to be stacked: a polariser and a variable ND from ND2 to ND32. That removes one element from the light path and with it the vignetting risk of two stacked filters. The darkening is set with a lever on the rim — in video the range can be run through smoothly even mid-take.