I spent a long time buying a filter because on the one hand I didn't know if I needed something like this and on the other hand because I had already tested a 0815 filter with miserable results and the costs for such a part are not insignificant. The question now was whether I should get several filters or a variable filter. In view of the price, the question ultimately became irrelevant. The first tests were able to dispel concerns that the image quality suffers, as with the filter mentioned at the beginning. The images are slightly blurry, but really only marginally. The weakest position extends the exposure time by a little more than 2. In my experiment (Nikon D7200, Sigma 18-35, K&F variable ND filter 77mm ND2-ND400 with adapter ring) I set the aperture to 2 in sunshine. 8 raised to expose well at 1/8000 without a filter. With the filter screwed on in the "MIN" position, the shutter speed went up to 1/3200. I turned the filter from mark to mark and came up with the following shutter speeds calculated by the camera: 1/3200, 1/3200, 1/2500, 1/2500, 1/2000, 1/1250, 1/800, 1/400, 1/125, 1/20(X-Cross, but underexposed). As you can see, hardly anything happens at first and the markings also do not allow any ND value order to be determined, which according to the logic of the first point is 2, the second 4 and the third 8.... So it's time to try it out. In the "MAX" position (1/20) the images are unusable because of the X-Cross, but this is really only the case in the absolute max position, and between the penultimate with 1/125 and Max intermediate positions are also possible where I got useful up to 1/30. So a usable ND value of 266 is calculated. This value is now completely sufficient for filming, because who says that I can't set the shutter speed higher than 1/60, which was the rule of thumb in the early days of analogue filming. Enough theory, I think the filter is an absolutely good investment.
Unscrewing is completely problem-free and if there was a color cast, it was due to the camera (Nikon D7200).
I've uploaded a few pics:
1.) 100% topless bottom view with filter at 5th position (1/2000)
2.) MIN - position
3.) Last usable position
4.) Filter to with X-Cross where the camera with the exposure of my camera (Nikon D7200) failed and I had to raise 2 values ​​in post-processing to be able to recognize something.

I took some fantastic photos of my grandchildren with this K+F 1/4 (67mm) Diffusion Filter. Ok they are my grandkids and incredibly beautiful and photogenic but this filter really made the pictures pop. It softened her skin and actually revealed more detail. I use a Nikon 750 with a Nikon 85mm 1.8 lens. I usually use a B+W F-Pro filter, which is very bright. I took most of the pictures with the K+F Diffusion filter on top of the B+W filter. It is incredible to attach the K+F filter. You simply screw in the ring and insert the filter. The latter attaches magnetically, but it's a fairly solid connection. The filter comes with a lens cover that also attaches magnetically, but not as tightly. I've noticed that it tends to come loose when the camera is pushed a bit in my camera bag. That's my only reservation about this filter. I also took off the B+W filter and used the K+F as the only filter on the camera. It works well, but I prefer to use both: I like the effect and I'm incredibly lazy too. The good news is that even with two filters, there was no vignetting.

The "K&F Concept 67MM Polarizing Filter Circular Polarizing CPL, Ultra Slim, Japan Optics, Multi-Coated, with Lens Cap" came in a branded box. It was nice to find the filter in a hard plastic case for protection, with a lens cap already attached to the filter. I ordered this filter for a Nikon P900. With the lens cap still attached to the filter, I carefully screwed the thin filter into place. I then took a series of pictures to check its effectiveness, and have included two pictures of the original Nikon lens cap showing the difference. When attempting to remove the filter, I found that it was stuck, so I had to resort to a filter wrench to remove it. The reason it got stuck was because I was turning the polarizing ring clockwise and counterclockwise from my perspective behind the camera. I must have just caught the threaded ring with my finger as I turned it counterclockwise, just enough to lock the filter in place. Some suggestions I have from using the filter; 1. When installing the filter, leave the lens cap on as it gives a larger shooting area. 2. Only turn the filter clockwise when viewing it from behind the camera to avoid repeating my mistake and lock the filter in place. 3. Carry a suitable filter wrench when using one of these filters just in case it gets stuck. 4. If it fits a P900 and it gets stuck. Zoom the lens so it points out about 30mm then remove the battery without turning the camera off. This will stop the lens retracting when the camera is off and if the camera is left on it will stop the lens trying to counteract the movement. 5. The lens and cap are stored in a small cellophane sleeve inside the plastic case. It is best to leave the lens cap on and insert it so that the flap of the cover is on the same side as the lens cap. This virtually eliminates the risk of the sticky flap touching the exposed filter surface. The only thing that would make this filter better is some sort of cover for the exposed surface or attachment points to hold the filter in place inside the case.

Purchased for use on a Nikon Coolpix P1000 the filter fits perfectly to the thread on the camera lens. The materials and the quality of the filter can be perceived both by sight and by touch. The filter itself is equipped with a thread where additional filters can be mounted.

I took some fantastic pictures of my grandkids with this K+F 1/4 (67mm) Diffusion filter. Ok, they are my grandkids and incredibly beautiful and photogenic, but this filter really made the pictures pop. It softened their skin and actually revealed more detail. I use a Nikon 750 with a Nikon 85mm 1.8 lens. Normally, I use a B+W F-Pro filter, which is really bright. Most of the pictures I shot with the K+F diffusion filter on top of the B+W filter. It is incredibly to attach the K+F filter. You just screw in the ring and pop in the filter. The latter attaches magnetically, but it's a pretty firm attachment. The filter comes with a lens cover that is also magnetically attached, but not so firmly. I noticed it tends to detach when the camera is jostled a bit in my camera bag. That's my only reservation about this filter. I also took off the B+W filter and used the K+F as the only filter on the camera. It works fine, but I prefer using both: I like the effect and I am also incredibly lazy. The good news is that even with two filters there was no vignetting.

I was in need of a 82 MM PL filter, I wanted some ND filters so when I saw both at a lower price than the PL alone for the name brand I usually buy I was interested. As someone who spent years selling photo equipment of the pro level to pros I want quality. using with two high quality lenses the Nikon 105 1.4 and Nikon 80-400.
Starting with the packaging the box was first rate, not just a cheap white box. The filters came with a case and I was expecting a wallet style, nice but inexpensive and I was please to see a high quality plastic case that provides better protection to the filters. Best designed case of it type I have ever seen, Thin design but thick strong plastic and with a unique rubber grip bonded in to allow filters of any smaller size to be securely held in place.
While the packaging an case are important the real deal is the product itself . When I opened them I didn't immediately identify the PL as it was the same thickness as the ND filters. Most PL are thicker because of the rotating nature of the filter which can be a problem with WA lenses. Thin often equal flimsy but not in this instance the metal rings are of high strength , the filter rotates smoothly and are of good optical quality.
A problem often encounter with PL filters is difficulty removing the filter, especially so with thin filters as pressure to the sides of the filter in removal will cause a filter to be temporaryly out of round and bind. With standard filters you apply pressure with the palm to remove the filter but that is not possible with a PL due to it's rotation. The thinness of the PL makes it difficult to just apply pressure to the sides and they have very thoughtfully made the two rings slightly different, The outer ring , the one you rerun to vary the effect of the PL is smooth, the inner ring has machined finish with narrow grooves that you can easily turn with a fingernail, a great solution . Of course part of easy removal is not to torque it down, it doesn't need to be tight.
Dont frequently review products but his is one I strongly recommend, especially at the value pricing.

I love this 77mm ND filter that fits perfectly with my Nikon 70-200 f2.8. I use step-up rings for other lenses like my 85mm f1.4. The ease of use is phenomenal and it glides so effortlessly. I love this filter. I would recommend it to anyone to push it down to the darkest, open the aperture wide and take a long exposure during the day for amazing results. Enjoy!

I chose the ND filter with a 77mm pitch to be able to use it with my Nikon lenses and possibly use adapter rings for smaller increments. Well packaged and easy to use. Easily correctable with slight dominants in post production. Very precise packaging that allows you to take it with you in total safety. Equipped with a Frantal ring with the various corrections indicated. Switching from one tier to another is easy and smooth. It can be used in both photography and video and easily achieves good results. We recommend buying specifically for value for money. Ideal for landscape photos and always to have with you.