In photography or video, we often fail to light, but it can also happen that there is too much to have a certain effect research. For example, if you want long pause in middle of the day to have a nice water, photography will be burnt even with the closed diaphragm. Same as video if you want to use a large aperture like F1.4 with a shutter speed of 1 / 50 second, the video will be too exposed. To solve these problem, we can use filters which reduces the light it's a ND fitres. I tested a variable ND filter 2-400 at ZOMEI.
Content of the box and technical characteristics
- 1 X filter ND2-400
- 1 X storage box
- Type: Variable ND filter
- Beach: ND2 to ND400
- Color: black
- Diameter of screw: 82mm
- Diameter: 86mm
The test
First of all, this filter exists in different diameter, for my part, I always take my filters in the largest available size, usually in 82mm. Because thanks to rings of adaptationn I can use the same filter on all my goals and I didn't need to buy several times the same filter (except you need on two different objectives at the same time). 
I rode on a 18-55mm 3.5 – 5.6 kit lens. You can see in the video above the result of the passage of ND2 to ND400 during the video. We can even for a video, the result is rather good, there is not default or significant to report aberration. This filter is good. This kind of variable filter is very convenient, mainly for video, to finely tune the brightness of the scene. For the photo, long exposure, these filters can also be used but not all their Beach. This isn't a question of quality, the phenomenon is also visible on a high filter range to 200 euro. During a long break to ND400 with this kind of filter, a cross over dark appears on the diagonal of the photo. So for pictures long exposure, it is advisable to take a ND 400 filter or 1000 fixed.
Conclusion
This 2-400 Variable ND filter performs very well this function, it is a filter with an excellent quality/price. His own faults to the variable ND filter, is also found on many models more expensive and is not specific to this model or this price range. The product link: https://www.amazon.fr/gp/product/B01LY483UX/ 