Heliopan Neutral Density Filter - ND 0.3. Heliopan Neutral Density filters are important tools for controlling light reduction. They permit less depth of field under bright lighting since the aperture has to be larger and, in addition, they permit long time exposures with stronger ND filters in sunlight. Over exposure can be avoided resulting in natural color reproduction. ND gray filters are manufactured from color neutral Schott glass so they can be used for accurate color imaging. They are available in 3 densities. Higher densities are available on special order for technical and scientific applications. Tip: For evening and night exposures, totally close the aperture, use a strong ND filter and use a tripod. Log exposures will result in moving objects disappearing and a surreal effect. For brilliant color reproduction, highest contrast and sharpness Heliopan filters are THE choice for the professional photographer. When coupled with the fact that Heliopan filters are manufactured from SCHOTT glass (the same stuff used to make ZEISS optics), it is clear that the only thing that should stand between your lens and your subject is a Heliopan filter. Made in Germany, all Heliopan screw-in filters come in high quality anodised brass mounts which virtually eliminate binding.