Anyone who likes to take photos knows what an ND filter is used for. Since my focus is landscape photography, I can't avoid working with such filters. I ordered this from K&F for my full-frame camera. I was just fed up with always filling my backpack with ND filters of different strengths. The Nano-X Pro was just what I needed. In order to use it on several lenses, I have it in the size 77 mm. ordered. I then work with step-up rings so that I can also use it on smaller lenses. To put it bluntly: I was impressed by the optical quality and the quality of the images! The processing is excellent and very successful. The lens thread is very cleanly cut. The filter can be adjusted from ND 2 to ND 32. The larger steps (f-stops) are marked on the ring and are easy to read. It can also only be rotated in this range from 1-5. It doesn't go below or above. So you always know what you have set by the stop. The 77 mm. Ring weighs 93 grams on my kitchen scale. Everything is massive and feels very good. The adjustment runs well with slight resistance. That's how it should be. The optical quality is absolutely error-free and the filter delivers top quality even in difficult lighting conditions. I did not notice any chromatic aberration or color gradients into green, magenta or anywhere else with pixel peeping. The quality of the filter is unsurpassed even with foliage or fir trees against the light and with reflections from dew. Finally an ND filter that does justice to my limited lenses and the full-frame sensor. The frame thickness with thread is only 9 mm. Without thread 0.63 mm. This means that the filter can also be used on wide-angle lenses without edge shadowing. Thanks to the two screwed brass handles and the ribbing of the ring, the filter can be adjusted very sensitively. Conclusion: K&F Concept has delivered a top filter here. What good is it if you put thousands into lenses and then bad filters make the job difficult or lead to lousy results? Clear 5 stars+ from me. I hope this is useful for your purchase decision. The price is also put into perspective because you save at least 4 ND filters. Thanks to the two screwed brass handles and the ribbing of the ring, the filter can be adjusted very sensitively. Conclusion: K&F Concept has delivered a top filter here. What good is it if you put thousands into lenses and then bad filters make the job difficult or lead to lousy results? Clear 5 stars+ from me. I hope this is useful for your purchase decision. The price is also put into perspective because you save at least 4 ND filters. Thanks to the two screwed brass handles and the ribbing of the ring, the filter can be adjusted very sensitively. Conclusion: K&F Concept has delivered a top filter here. What good is it if you put thousands into lenses and then bad filters make the job difficult or lead to lousy results? Clear 5 stars+ from me. I hope this is useful for your purchase decision. The price is also put into perspective because you save at least 4 ND filters.