In terms of build quality, this is a pretty good filter. The threads are good for a budget filter and do not bind easily. The adjustment ring is a little stiff but still pretty easy to maneuver. There are also hard stops at the beginning and end of the filter's range to prevent you from over-rotating.

Unfortunately, this is another poor showing from K&F in the area of optics. To the filter's credit, there is almost no color shift and no vignetting or x-pattern within its functional range. However, there is a major loss in sharpness that, in my testing, is the worst at the middle of the filter's range and improves slightly at the beginning and end of the range.

You could film with this filter if you had to, and you would get OK results as long as you don't crop your footage at all, but clarity and overall image quality are going to fall off quickly if you do try to crop in. I would only use this filter as a last resort, and my personal recommendation would be to spend a little more money to get a Freewell VND for around $100 that in my testing has virtually no loss in sharpness or clarity.

The image attached to this review shows a 100% zoom where the photo on the left was taken with no filter and the photo on the right was taken with the K&F VND at approximately the middle of its range.