Used Cokin 55mm Pure Harmonie Super Slim Variable Neutral Denisty (ND) Filter - 0.3 to 2.4+ (1 to 8+ stops)

Cokin PURE Harmonie filters are the thinnest and the lightest in the world. With a thickness of 4.5mm, they are almost invisible when mounted on your lens. Their weight is so light that you won't even notice that they are attached.

Cokin PURE Harmonie filters have been engineered with no compromise: very robust, compatible with all lens caps. Super lightweight for maximum AF performance and ultra-shallow profile to prevent vignetting, they are just perfect. They are PURE.

Neutral Density filters are used to reduce the quantity of light that reaches the sensor of the camera. They allow you to decrease the shutter speed in order to achieve motion blur (waterfalls, ocean, clouds ) 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 0.3 (1 f-stop) to 2.4+ (8+ f-stops) by rotating the front ring.