[Brass] Very pleased with this filter .....plays well with my D850 and Tamron 24-70 mm G2 lens

[0.545 lb] Seems to be reasonable quality. Nice slim ring for wide angle lens.

[Brass] Works perfectly with the lens

[72 mm] https://youtu.be/PexWWSgvwDE?si=d7Hr_YQ3kgdMz14u
You can see how it works on our youtube channel.

[0.545 lb] A filter like this is a MUST HAVE if you want to level up how your images (for photography and video) look in broad, intense daylight in one fell swoop.

They reduce the overall amount of light coming in the camera so you can stop down for a beautiful optically blurred out background and heavily reduce intense sunlight reflections, virtually adding dynamic range in daylight. I knew this would help my shots but my jaw dropped when a got the footage back from testing locations for a project, with and without. (attached photos are screen grabs of video. Shot on Sony A74, Sigma 24-70 f2.8) *Note: This is my first ND filter and first polarizer.

My testing has found a slight cyan cast in the area where sunlight can hit the lens where shadows can be seen, it looks almost dreamy and I kind of like it, but not perfectly color preserving. With Nano-X Pro, I have not encountered any dark X pattern no mater how I adjusted it, which is far better than most Variable ND + Circular Polarizer filters on the market. The included pouch is made of materials that feel great in the hand and its pull tab that makes the filter rise out of the pouch is a very nice touch that makes me wish K&F Concept included this pouch with more filters and also sold separately. I want other filters in these things! (Wile they do sell other pouches. They do not sell the ones included with these filters.)

If you are on the fence and don't have a ND or polarizer, just get it. It took a while for Polar Pro to finally release something like this, and the price of this one STILL undercuts it. If you are a videographer/photographer, image quality is super important and this is a fantastic tool to help you properly expose your shots. There is a reason why Directors of Photography have built in ND filters on their wish list for their cinema cameras and this is why, it makes their job so much easier and allows them to focus on building the look that they want.

[Brass] I've used it exclusively on the Tamron 28-75 and sometimes a Tiffen Black Mist, i have no issue. Some reviews may be exaggerating its issues, but some are facts and other are minor hustles.

[0.545 lb] I am a film photographer and I bought this for my Pentax f/1.4 50mm lens to shoot long exposures of waterfalls. For such a low price I was prepared for problems but all of my images were beautiful and consistent, no difference in picture quality at different exposure times and different lighting conditions. The fact it is waterproof was greatly appreciated since the spray radius off some of the falls was quite impressive. Overall very pleased especially for the price, I would def buy from this brand again.
Good to note: I primarily shoot black and white, and the only color shots I took with this filter were at night, so I can't really speak to how it might affect colors. What I did shoot looked accurate and I don't see any discoloration.

[Glass] The K&F Concept Nano-X Filters are well made. I've purchased two 67 mm and one 77 mm and all three fit my lenses perfectly. Optically they have no practical effect on image resolution or light transmission and produce no added glare. These are well-made, reasonably priced filters with exceptional optical performance. It's amazing how much multi-coating technology has improved in the last decade and K & F seems to be fully competitive with the best filters available anywhere.

[Brass] Excellent CPL filter, very true to colour and superb optics I love the NiSi 77 mm filters and use them on my Nikon f2.8 lenses

[0.545 lb] It works well without shifting colors. The ring has trouble to stay attached with the lens, you have to force a bit to have it served to the lens.
I got the first one with a scratch on the coating, B&H exchanged it immediately. You are the best customer service!