Heliopan Variable Grey ND Filter Slim (0.3 - 1.8) - 60mm (ES 60)Heliopan Variograu Slim ND 0. 3 ND 1. 8 Filter 60mm (ES 60) Made in: Germany Diameter: 60mm Exposure: Increase by 1 to 6 Stops Ambitious or professional photographers will at some stage reach the point where both the setting options of the camera and the spectrum of the film is exhausted. Sometimes the photographer simply wants a longer exposure time than the camera can offer, to achieve a properly exposed image. For example this can be the case if