Heliopan  Graduated Neutral Density 4x Filter

• Slim mount does not vignette with 21mm lenses.
• Minimal reflections because of matte black anodized brass filter rims which will not bind when threaded in combination with other metals.

The Heliopan Graduated Neutral Density 4x Filter is a neutral density filter that gradually increases in density from one edge of the filter to the other. This allows the photographer to control overexposure in sky areas for example. This 4x filter has a 2 stop variation.