already have a few filters at home, including the K&F Concept Nano-X ND Filter 77mm Variable Gray Filter ND2-32 for 75 euros, which I use on my wide angle, for example in bright sunshine (for shooting with an open aperture) and for Long exposures and that's really good. Now I was allowed to test the variable ND filter from the PRO series from K&F, a filter for a whopping 280 euros. Anyone who already works with filters should of course also use high-quality glass on a high-quality lens, but a filter for just under 280 euros is not a pittance and this investment should be well considered. What I can say in any case: The filter is not only great in terms of price but also in terms of performance and processing. It starts with the presentation (packaging) of this filter, neatly finished bag with magnetic cover, suede applications, soft and lint-free lining on the inside, a side strap with which the filter can be transported by pulling it upwards. The filter itself is very well made and easy to use with the two brass tabs. It has a very nice resistance when adjusting, not too heavy and not too light. The glass shows no defects and the threads are cut absolutely clean. I can only say about the image quality/image performance: TOP! There are no color errors / color casts or anything else negative. So I can work with my lens in bright sunshine even with an open aperture and, if I like, also realize long-term exposures with a slightly closed aperture with the help of the filter. As I said, image quality is as good as if I had no filter on the lens at all and that's how it should be. The pictures I uploaded (modest test shots) were taken wide open and against the sun. My conclusion about this filter: Very high-quality processing / image quality impeccable / feel excellent. Price very high Now everyone has to decide for themselves whether such an investment is worth considering.