First off, I'm a fan of K&F's products, I try to use them as much as I can during photo sessions, since they just give good consistent results.

However, the ONE complaint I've always had, is that K&F's product line was quite limited to low to mid range products. Don't get me wrong, they are amazing for what they are.. and I LOVE having them on location. But, as with any product I use in the field, they're often NOT the same products I will used in a fully controlled environment. In a perfect world, I would be able to take all of my studio gear on location, and not have to worry about potential damage to my gear.

To that end, K&F's mid-range type of filters and equipment have worked extremely well..

However.. I've always wondered.. what if my preferred manufacturers actually produced higher end gear.. would the results be as good? Better? What might I be missing, by taking certain types of gear, over others?

When I saw that K&F was producing a 'Nano' sort of lineup, a while ago, I was excited.. but also somewhat concerned... I already had my high end filters that I would use on special occasions, and for studio work... would K&F be able to actually meet that quality? If so.. could I stop buying gear from manufacturers that I didn't want to use, due to their awful customer support practices?

When I saw this filter pop up on my recommended feed.. my curiosity got the better of me, and I had to order it.

I grabbed the 82mm version, since my primary workhorse lenses are 82mm. Sigma 24-70mm f/2.8 DG DN Art, is commonly my 'Go To', though having rented and used a Tamron 35-150mm f/2-2.8 Di III, a few times, now.. and having it on my wish list.. both use 82mm filters.

After using it for a couple of sessions, now... both studio and on location, I have some initial short term thoughts:

Exposure change is minimal. - This is a big deal, since so many 'cost effective' polarizers will often drastically impact exposure. I've seen some filter change the EV by as much as a full stop. At that point, a CPL is operating more like a slight ND filter, and is not really optimal if all you're wanting is glare reduction. This one, I would say reduced the EV by roughly 1/8th of a stop when installed.

Color shift also seems to be minimal, if there is any at all - CPLs are also often plagued with the problem of changing the color of a scene, when they're applied, and in the case of variable polarizers, you may even experience a color shift while adjusting the amount of filtering being applied. This isn't ideal, as it just means you're going to have to do more color adjustment in post. Now, that said, keep in mind, the way a variable CPL works, if that if you reduce the glare from a source that is producing a color cast, you WILL have some color shift. This is just the nature of light.. similar to using a gold colored reflector for a subject illumination. If you remove the gold color from the reflector, there WILL be a color change. This is not the same as a filter created color shift.

Distortion seems to be non-existent - This is ANOTHER problem that so many filters (in general) have, and can often be so slight, as to not be seen until you're working with your files (RAW or otherwise) in post. I've seen a large number of filters absolutely ruin photos in the past, so it's something I tend to be VERY twitchy about. This filter seems to have no distortion at all. I'm EXTREMELY happy for that.

Quality & build - This filter has 2 parts to it. When I say that, I don't mean there's 2 physical parts that you have to attach... just that there is the static mount, that attaches to the end of the lens, and the adjustable portion that floats and rotates on the end. The static mount is actually a bit on the small side, which means if you are going to be attaching this to your lens, with any bit of snugness, you may want to use a filter tool for it.

NOTE: This filter does NOT have a forward facing threaded mount. If you use a lens hood that attached via the filter threads, it WILL NOT WORK with this filter. Additionally, the lack of a forward thread also means you cannot stack this filter with others, OR you will want to use it as your last filter in the stack. I know.. there is some photographer out there, right now, reading this, who is screaming that you shouldn't stack filters, ever.. but you saying that, doesn't change the fact that there ARE those that do. If you DO still want to use the CPL as a middle filter, you're going to need to get some external mount adapters to do so.

Case - The case the filter comes in, is actually a nice little leather and denim case, with a pull string on the side, that will push the filter out for you. My only gripe with this case, as with so many others, is that it'd be nice if the case had a small insert for a label. When carrying around a kit of filters, and you're operating in lower light conditions, it's often a pain to read the edges of the filters to determine which one you're grabbing. Adding a small label pouch would be an awesome addition.

Un-important - The packaging of the filter is quite nice, having a sturdy foam framed box, and including a microfiber cloth is a nice touch. The fact that the box turns into a 'picture frame' is gimmicky, and borderline insulting, as if the average person buying this were a child, who may become super excited over using a dense foam-board package as a photo frame. It's a $180 lens filter... the person buying this isn't going to spend that, and then not buy a decent frame for any photos they produce. This sort of marketing gimmick might work for those individuals buying a $20 CPL for their instagram photos.. but this filter is clearly aimed at the higher end photographer.

So.. that brings us to the big question.. how are the results? Honestly, I can't find a reason to complain at all. Colors come through as expected, no distortion, and absolutely no image reduction. The smaller mount point on the front lens element keeps flaring down to a minimal, and produces nice, crisp fantastic images.

The variable polarization works as expected, but I would have liked to see it spread a bit more evenly around the lens. Right now, when I turn the adjustment ring, there seems to be an awful lot of lack of polarization for a good amount of the filter, before the polarization kicks in, quickly.. a more gradual approach would have been preferred, BUT, that's nothing different from the current high end CPL I'd been using, either.

Which brings me to the price... at the currently listed price of $180, this filter is squarely in the upper end pricing for a CPL, which is an area that is already a rough spot to be in, since CPLs usually start to lose their price to performance around the $100-150 range. The $180 range now places you clearly in the range of B+W, Zeiss, and Hoya... 3 of the big names that dominate that market spot. It DOES perform on par to may of those products, but then again, you also have companies like PolarPro that have been making leaps and bound in that area, too, with the latter being VERY aggressive in their price to performance. I've had experience with all of the above, and while I really like K&F's customer service, and the fact that they're a LITTLE cheaper than many of the aforementioned brands, it doesn't change the fact that they MIGHT be pricing themselves out of the competition. If this filter was aimed at a lower price point, say $130-150, it might be an easier pill to swallow, especially if you're the type that wants a separate filter for every lens in your kit (as opposed to using a step down/up filter set).

That said, so far I'm immensely happy with the results I'm seeing with this CPL, and I'm cautiously optimistic that my long term experience will keep me comfortable with this CPL... time will tell, but for now, I'm cautiously recommending it, even at its current price.

I tested the K&F Concept Nano-X PRO series polarizer 67mm with the Sony A7RII on a Sony SEL-20F18G. I use polarizing filters for 99% in landscape photography. Since the effect is virtually impossible to simulate in post-processing, a polarizing filter, in addition to grey filters, is one of the only material filters that I regularly use.

The K & F is one of the slim filters. This can prevent vignetting in an extremely wide angle, but the slim frame makes handling much more difficult. Due to the design, this is the case with almost all manufacturers. After all, the filter has a threaded socket at the front, so that several filters can be screwed one behind the other. Depending on the type, the lens hood and lens cap can also be fitted. The filter comes in a high-quality, sturdy bag with magnetic closure. As a little gimmick, the manufacturer also includes a microfiber cloth for cleaning.

The thread can be unscrewed cleanly. The rotating frame runs smoothly and smoothly. The slim design makes handling sometimes very difficult. On the one hand, you have to be careful not to screw the filter too hard onto the lens, otherwise loosening it by hand will be difficult. On the other hand, when turning the filter counterclockwise, there is a risk of unintentionally loosening the filter if it is not screwed on firmly enough. With the lens hood attached, operation is also no longer possible.

The glasses come from the Japanese house Asahi Glass and appear to have a high-quality finish. I was unable to detect any loss of sharpness even at extreme magnification. I was able to notice a slight color deviation into reddish. However, this is really barely noticeable. Since my used lens is not susceptible to lensflares, I was happy that there was no deterioration with the filter on. The filter absorbs almost exactly one f-stop of light, which is a very good value. The filter effect is good, but I honestly didn't expect anything else in this price range.

In my attached pictures, you can see the result with strong backlight, both with and without filters. I couldn't find any differences in quality or lensflares here. You can easily see the filter effect on the leaves on the other two pictures. Here, sunlight falls on the shrubs at an angle of about 90 degrees. The polarization effect is clear. The white balance was set manually to daylight for all shots. The only very slight color shift is barely visible here.

So far, I haven't had K&F Concept on my screen in this price range. The results of the filter are first-class and do not reduce the quality of my high-quality lenses. Unfortunately, you have to live with the somewhat difficult handling of this design, and K&F is not reinventing the wheel here either. However, I give the full five stars for optical performance.

I have tested this “K&F Concept Nano-X PRO series polarizing filter” extensively with my two 67mm Sony lenses (85mm + 24mm focal length) and would like to share my experiences today: The packaging of the filter is impressive, because “K&F” has this “Pro” Filter very attractive and well packaged.

You will receive a bag with leather parts, which is softly lined on the inside and is used to store the filter. In addition, an extra packed cleaning cloth is included. The bag has a magnetic closure and is very well made all around. The filter itself is also very well made, it has a brass frame and can be easily screwed onto my two lenses. Turning the filter to adjust also works well. Due to its slim design, the filter also does not apply too much to the lens.

The surface of the polarizing filter has been coated on both sides with a 36-fold nano coating, making it waterproof, dirt-proof and scratch-resistant. The coating makes the filter robust and I assume that this makes it durable and allows me to shoot with it for a long time. I am also completely satisfied with the properties of the filter, it reduces reflections (e.g. in water) by eliminating polarization by around 99% and the contrast of the image (easy to see when taking photos of sky/clouds) is also increased.

I've already been shooting in the landscape with the filter, I'm very satisfied with the image quality. I did not notice any visual disturbances caused by the use of the filter. I can recommend the “K&F Concept Nano-X PRO series polarizer”.

Tested for video on my VG30 and works like a charm. It comes with a nice carrying case. Remember: You need to install on the front of your lens and then turn clockwise or counterclockwise so you can align properly and get the elimination of reflection that you are looking for.

I've become a big fan of K&F Concept filters. I have quite a few of their ND/VND filters and a Nano-X series CPL filter that is simply excellent. This is my first Nano-X Pro series filter and while the others are high quality this one is on another level entirely.

The filter has a coated CNC machined brass that attaches to my lens smoothly and comes off without binding. It's slim to minimize any possibility of vignetting yet retains front threads to attach other filters. The edges are knurled and move with a slow liquid feel that helps the filter stay adjusted where you want it. The filter has K&F's Nano-X 36 layer MRC coating that resists glare, fingerprints, etc. and makes the filter easier to clean.

It comes in a slim leather case with magnetic clasp and drawstring that lifts the filter up when you pull it - this is a great feature that helps keep fingerprints off the glass.

As with my other K&F filters this one is extremely neutral without any color cast that I can detect. It has replaced my older B+W CPL filter in my bag and takes the place of my Freewell magnetic ND system when I want to travel light. It's K&F highest-end filter and compared to the competition it's cheaper and better quality making it a fantastic all-around value. Highly recommended.

This is a really, really nice CPL filter. It has a very slim design so it doesn't result in any vignetting, even while using may long telephoto lens.

Threads onto my lens easily without issue.

Adjustment of the polarizer is smooth and predictable.

There's no color shift or any other artifacts from the filter. Just crisp images with accurate color.

The filter comes with a nice fabric storage case, along with a microfiber cleaning cloth.

There's also a little instruction card that details how to use the box the filter was packaged in as a photo frame. Kinda kitschy but whatever. I just tossed it.

Great quality though.

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Since the filter was positioned as a member of their flagship lens filter line I definitely had already high expectations in the K&F Concept Nano-X PRO CPL filter.

It certainly made its first impression while unboxing it -- it comes in a stylish box and inside that box is an elegant leather filter carry case.

But more important is of course what it delivers in front of a lens. And that is indeed amazing: I tested it on different lenses, a 70-200 mm lens and on a 35mm. Based on physics of a CPL filter in general it is not advised to go wider than 24mm.

I found no distortion problem; reflection and glare get well mitigated; no vignetting or spots, or dark areas detected within the focal lengths mentioned. Also, of course, keeping a certain angle towards the sun will determine the outcome.

That is definitely a high-end filter and I think K&F has made it into the professional market and its expectations.
I was happy with the test results and can recommend this filter, it is a well-worth investment, and my motto is 'better no filter at all than a cheap and bad filter'.

This filter and its packaging exudes quality. But of course, it all comes down to the filter itself, regardless of how nice the packaging and presentation, and this filter didn't disappoint.

I tried it out on my Nikkor 24-85 on a Nikion D800 for a few basic comparison test shots (see my pictures). The polarizer is easy to turn and feels fluid. Dialing in the right spot is pretty easy. I noticed no degrading in the image quality, attesting to its glass and coating quality.

It comes in a really nice case with a wrist strap. The box can even be converted into a picture frame... pretty clever. It also comes with a vacuum packed lens cloth, which I haven't opened yet, so I can't say how nice it is. Overall, it seems like a very high quality filter for their new flagship Nano-X PRO Series.

K&F Concept Nano-X PRO Series Polarizing Filter 67mm

From the packaging to the finished image, everything at the highest level. Quality and workmanship of the filter is top top top. It turns smoothly into the lens thread without cramping. The rotation mechanism has a good resistance and can be adjusted perfectly. The image results are convincing and I could not notice any negative effects. (Color fringes or the like)

Now how do you evaluate the price of such a filter? I think people with photographic experience know what such a high-quality filter costs. I think the price is quite reasonable for the high-quality and very well-made filter.

Aunque tengo un filtro de esta misma marca que hace su función correctamente, no permite modificar la luz y el contraste. Este filtro sí lo permite, aunque sutilmente, permite girar suavemente la lente una vez acoplado y modificar en luz, contraste y color la percepción de la imagen. No es un cambio con mucha variación, pero permite retocar levemente la intensidad con que se capta una imagen.
Se le podía poner un punto negativo por el precio, pero, en mi opinión, es una valoración personal y relativa.
La calidad es muy buena y cumple perfectamente su cometido.