K&F Concept Nano-X CPL Polarising Filter True Color Ultra-Low Reflection, 37 mm

Nano-X — polarising filter 37 mm, cuts reflections and deepens colour. It earns its place in landscapes, by the water and when shooting through shop or car windows, where reflections otherwise drown colour and detail and the sky stays pale.

• 28 anti-reflective layers, reflectance 0.1 %
• Screws onto a lens with a 37 mm thread.
• The surface repels water and grease and resists scratches

A polarising filter takes the glare off water, glass and foliage, and with it brings out the colours that were hiding underneath. The sky darkens, clouds stand out, leaves stop flaring white and you can see through the surface of water. The effect is set by rotating the filter and is strongest at right angles to the sun; it cannot be recreated in post, because it is a property of the light rather than a colour in the file.

The glass carries 28 anti-reflective layers and reflects only 0.1 % of the light, so no ghosting or veiling appears against the light.

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.

Ordinary polarisers pull the picture towards yellow-green and the colours then have to be straightened out in post. The titanium coating suppresses that shift, so snow stays white and water keeps the tone it actually had.