K&F Concept Import Optical Glass HD/Waterproof/Scratch Resistant Variable ND2-ND400 (1-9 Stops) ND Lens Filter with Putter for Camera Lens K&F Concept Variable ND2-ND400 Filter is a must-have for landscape photography ! The K&F Concept Variable ND filter operates on the same principle as a Circular Polarizer rotate until you reach your desired effect and shoot. It allows you to have continuous control over the amount of light coming through your lens in an approximate range of 1 (ND 0.3) to 9 (ND 2.7) stops while maintaining the integrity of your image. Provides 1 to 9 stops of light reduction control. Ultra Slim 7.4mm. Ultra-slim frame support no vignetting at 16mm focal length. Comes in K&F Concept professional packaging with PU leather Case. Made with Japanese imported optical glass using K&F Concept Nanotec technology. Note: When using the ND filter to the maximum(ND400) or bigger degree density, it will appear "X" spot or a blur in the picture, this is a normal phenomenon. (Suggestion: Lower down the density value gradually and reduce the aperture, until the facula disappeared.) Features 1: Import Optical Glass This ND filter is made by importing Japanese AGC optical glass, a total of 28 multi-layer coatings, effectivly reducing reflection from the filter itself and glaring, ensuring high-quality image. Features 2: Putter Design Frame designed as a putter can help you accurately adjust the stop, video shooting users can automatically adjust the stop via auxiliary tools, each stop from ND2 to ND400 be marked on the frame conveniently for 360-degree rotation to adjust the stop, multi-scene application. Features 3: Waterproof & Scratch Resistant Both glass sides of the K&F Concept ND filter with multi-layer hydrophobic, oil-proof, and scratch-resistant coating, protecting the nd filter all around, suitable for adventure use. Features 4: No Vignetting For the filter designed with an ultra-wide-angle design, the ultra-slim frame is only 7.4mm, supporting in 16mm telephoto and wide-angle lens no vignetting, due to the difference in lens type and focal length so this filter might be met dark"X" cross, this isn't the quality problem, it can disappear via rotating the filter. Features 5: Leather Carry Case :This ND filter case is made of PU leather, side pull design can take out the filter conveniently. What's in Box 1* ND2 to ND400 Filter 1* Carrying Box(Color of box is sent randomly, with the same filter) Q&A Q1: How does ND2-400 work? A1:Polarizers with high transparency are used to control the amount of light entering the lens through the filter. Q2: Can the original lens cap be used for ND2-400? A2: In order to prevent vignetting, the ND2-400 is designed with an ultra-wide angle structure. The front port diameter of the filter is one size larger than the original aperture of the lens, so the lens cap needs to be one size larger than the lens aperture. For example, the 77mm ND2-400 Need to use 82mm lens cap. Q3: Does ND2-400 have a color cast? A3: Due to the use of polarizing film to control the amount of light entering, color cast is a common phenomenon among all adjustable NDs on the market. KF relies on mature manufacturing technology and fine coating technology to minimize the polarization effect of the polarizing film. Q4: Does ND2-400 have vignetting? A4: Using Nikon Z 7 and Nikor 14-30mm Sline test, 14mm vignetting is not obvious, 16mm has no vignetting. Q5: Does ND2-400 have a cross shadow? A5: The maximum aperture of an ultra-wide-angle lens below 24mm will have a slight cross shadow in the 1-5 gear dimming. The longer the focal length used, the smaller the effect of the cross shadow. There will be obvious cross shadows and vignetting in the large gear of dimming. If you continue to rotate the shadows, the shadows will disappear naturally, which is a physical phenomenon and not a product problem.