Neutral Density filters are used to reduce the quantity of light that reaches the sensor of the camera. They allow to decrease the shutter speed in order to achieve motion blur (waterfalls, ocean, clouds, etc.) and/or to reduce depth of field in very bright conditions. As they are “neutral”, ND filters do not affect color rendition. With PURE Harmonie Variable Density Neutral Gray filters, users can select the intensity from ND2 (1 f-stop) to ND400 (8+ f-stops) by rotating the front ring.
Pure Hamornie ND X filter is the result of extensive engineering. That’s why it is thinner than any other variable density filters. It’s form factor has been designed so that the external diameter of the filter is wider than the front of your lens, to avoid vignetting issue that may occur.
While some vari-nd can become yellowish when increasing density, PURE harmonie ND X filter remains perfectly neutral.