Nikon’s 800mm F5.6 FL ED VR and 400mm F2.8 FL ED VR lenses earn the ‘FL’ in their names from the coating of fluorine applied to the lens elements. But what exactly is fluorine coating, and why is it important? In this video from Nikon Japan, the coating’s repellent properties are demonstrated as a variety of liquids are dripped, drawn and painted onto the lens surface. See video
News: Digital Photography Review (dpreview.com)