If used with very wide lenses, the X-effect may occur above f/9. These layers also provide a higher maximum light transmission and a more consistent transmission curve for truer light reduction. Urth 58mm ND64-1000 (6-10 Stop) Variable ND Lens Filter Plus+ provides 6 to 10 f-stops of light reduction, giving you greater creative control in bright-changing light. Urth 58mm ND64-1000 (6-10 Stop) Variable ND Lens Filter Plus+ range features 20 layers of nano-coating providing easier cleaning and better protection against water, oil, and scratches. By blocking 6 to 10 f-stops, you can use wider apertures in bright variable light for shallower depth of field effects, and slower shutter speeds for long exposure effects without overexposing your images.