Below, I'll share my unbiased experience with this item, hoping to help you make a more informed decision about a potential purchase. While I try to be as objective as possible, this is always my subjective opinion.

The 58mm ND2-400 Variable ND filter is an essential accessory for those who want greater control over exposure in their DSLR photography.
This filter, with a variable ND2 to ND400 (1.9 f-stop light reduction), allows you to precisely adjust the amount of light entering the lens. It's ideal for shooting in bright light or for achieving creative effects like silky smooth water or moving clouds.

One of the aspects I most appreciated while using this filter is its thin construction, which helps prevent vignetting even at wide angles, a common problem with thicker filters. Furthermore, the 28-layer Nano X coating ensures excellent light transmission and effectively reduces reflections and ghosting, improving overall image quality.

From a practical standpoint, the adjustment ring is smooth and precise, allowing you to quickly vary the incoming light density without having to change filters. In this regard, I found it particularly advantageous to be able to gradually adjust the amount of light during my photo session.

In conclusion, the 58mm Variable ND filter is a quality product, ideal for amateur and professional photographers who want to experiment with exposure and achieve professional results without complications.

So, for everything written above (based on the item received), my rating is 5 out of 5 stars.

I am fairly new to photography but we did get a chance to use the filter a bit on vacation and it worked as we expected it to. Probably will work better as we learn more.

I'm very happy to have been able to test this variable ND filter, which has found its perfect place in my camera bag, whether for video or still photography (especially in bright sunlight).

If you're not familiar with this type of filter, an ND (for "Neutral Density") is a gray filter that reduces the amount of light entering the lens, but without altering the colors or white balance. In short, it allows you to film or photograph with "creative" settings (wide aperture, slow shutter speed) even in bright or very bright light.

This model is described as "variable," meaning you can adjust the level of darkening simply by turning a ring. This is really very practical when the light changes rapidly, such as during outdoor filming in broad daylight.

I tested it on my OM-1 Mark II with a 12-40mm f/2.8 lens and filmed at 1/50s in the middle of the afternoon while maintaining a good depth of field. If I didn't have this filter, I would have had to stop down to f/11 or wider, thus losing all the background blur that looks so good.

One important technical point to keep in mind: below a focal length of 19mm, you're very likely to see a phenomenon called the "X effect" or "X-cross." This is actually a sort of dark cross that appears in the center of the image. It's caused by the interaction between the two polarizing layers of the filter when it's pushed to its extremes. It's not a manufacturing defect; it's a phenomenon common to all variable ND filters. To avoid it, you should stay above 19mm for photography, or 17mm or wider for video.

The optical quality, however, is impeccable: no color cast, no visible loss of sharpness, it's clean.

The multi-layer coating repels water and dust well, and the small orange handle allows for precise adjustments without touching the glass. The threading is very well finished and the whole thing feels very solid.

The only minor drawback is that the filter prevents the use of a lens hood, and you'll need a 67mm lens cap if you want to protect it (the filter, although 62mm, protrudes slightly). Nothing major, but good to know.

The 67mm ND2-ND400 filter from the Nano-X series isn't the first ND filter from K&F Concept in my collection. I already use the CPL&ND2-ND32 (2-in-1 filter) from the Nano-X series. Therefore, I knew what to expect before ordering. However, my expectations were even exceeded.

The ND filter comes in truly high-quality packaging and includes a faux leather storage pouch with a discreet magnetic closure and a simple yet functional pull tab for removing the filter. I much prefer this to the basic plastic cases usually used to protect filters.

Thanks to the precisely fitting threads, the filter screws in easily and almost silently. The nine aperture settings are easy to adjust thanks to the generously sized lever. At the same time, there's enough tactile feedback to always feel the change.

Thanks to the nano-coating, the filter is easy to clean; water simply beads off!

CONCLUSION: A truly high-quality ND filter from K&F Concept, which, while not exactly cheap, seems quite affordable compared to other competing products. You really get top quality at a relatively fair price!

-----------------------------

INFO: This product was provided to me as part of an Amazon Vine product test. Vine products are provided to product testers free of charge. However, the resulting benefit in kind must be declared for tax purposes. Therefore, I review all products to the best of my knowledge and belief, just as I would for a regular purchase.

As a big fan of K&F Concept products, I'm particularly impressed with this variable neutral density filter from the Nano Xcel series: For this price, it offers first-class quality, and I now use it on all my lenses. The extremely slim frame (only 7.4 mm) ensures that there is absolutely no vignetting at focal lengths of 17 mm and above. The stepless adjustment from 1 to 9 f-stops allows me to create long exposures in landscape photography as well as precisely control the brightness in video.

Thanks to the 28-layer nano-coating on both sides, made of high-quality Japanese glass, there are no distracting reflections or ghosting, even in backlit situations. Waterproof, oil-resistant, and dustproof, this filter withstands all weather conditions and reliably accompanies me on every outdoor adventure.

I recently tested the K&F Concept Nano-Xcel 67mm ND Filter and was pleasantly surprised by its performance. I'm not entirely sure whether the physical principle is similar to that of a polarizing filter, but one thing is certain: the filter does its job very well, and the results are visible.

Features and Performance
The ND2-400 filter is a variable neutral density filter that, by rotating the dial, allows you to cut light from 0 to 100%. You go from high brightness to drastically reduced light, almost as if you were adjusting the lens aperture. The ability to precisely adjust brightness is very useful in situations where ambient light is difficult to manage, such as when shooting in broad daylight or when you want to achieve a long-exposure effect in bright sunlight.

Build Quality
The filter is well-finished, with high-quality materials that give it a solid and durable feel. This isn't a cheap accessory, but the price is justified by the build quality and precision of the filter. The adjustment ring is also smooth and easy to use, without excessive resistance or annoying play.

Use
When mounted on the lens, the filter primarily serves as a brightness regulator, allowing for properly exposed images even in bright light. It's a useful accessory for those, like me, who still use their camera to capture memories and landscapes, especially in situations with strong light contrasts. It's particularly suitable for landscape photographers or those who enjoy long-exposure photography, such as those that create silky water effects.

Elegant and Practical Case
Another thing I really appreciated is the included case, which is elegant and practical. Not only does it protect the filter from dust and damage, but it also has a design that matches the overall aesthetic of the product. It's comfortable to carry and can easily be slipped into a camera bag or backpack.

Conclusions
Overall, the K&F Concept Nano-Xcel 67mm ND2-400 is an excellent accessory for photographers who want precise light adjustment in their images. The product quality is very good, and it's truly useful for achieving creative and professional effects. I recommend it to anyone with a camera looking for a high-quality, practical, and well-built ND filter.

K&F Concept Ultra-Low Reflectance ND Filter 67mm – Variable ND2-400 (Nano Xcel)

(1–9 stops, 67mm diameter)

✨ My impression:

A truly high-quality variable ND filter that is absolutely convincing in terms of feel and functionality. I primarily use it on my 67mm lens for outdoor shoots and quick video recordings – and so far I'm completely satisfied.


✅ What I particularly like:

I received this product for free as part of the Amazon Vine program for testing purposes. Of course, my following review is still neutral and honest.

At the time of this review, the K&F Concept ND filter with a 67mm thread costs €83.99.

Among the two other K&F Concept products I've tested so far, this ND (Neutral Density) filter clearly stands out. The camera bag and tripod I've tested previously were "okay" for their low prices, but nothing groundbreaking.

This ND filter, however, is in a completely different league! The packaging alone exudes quality. The filter is nestled in a nicely printed cardboard box with a magnetic closure, inside of which is a high-quality (faux?) leather pouch with the K&F Concept logo embroidered on it, also with a magnetic closure. The high-quality filter is finally inside this pouch.

My equipment consists mainly of the Panasonic G9 II, Panasonic's current Micro Four Thirds flagship for photography. During testing, I had the choice of ordering a filter compatible with either my Leica 12-60mm lens or my Panasonic 100-300mm lens, and I opted for the latter. Since I primarily photograph outdoors and in nature, especially in good lighting conditions, this filter is perfect for me.

Screwing it onto the lens feels excellent, and the ND filter's ring, made entirely of aluminum, is of high quality and shows no flaws or mechanical imperfections. Once screwed on, it also features a small, aluminum grip on the ring, which allows you to select the desired exposure level.

The ring rotates freely without any limit or noticeable increments. Instead, there's a scale on the ring itself that indicates the exposure increment. With the filter fully open, you can hardly tell the difference compared to a photo taken without it. You'd have to do some extremely precise pixel peeping to tell whether one photo was taken with a filter or not, and even then it's difficult to distinguish, because unscrewing the filter inevitably changes the angle of view to the subject/comparison photo. That's exactly how a variable-adjustable filter should be—excellent!

What's truly outstanding, however, is the very, VERY wide aperture range of up to 9 steps. I haven't yet had the opportunity to use the filter in the exact scenario I have in mind (e.g., a stream, lake water in the wind, etc.), but in initial tests in the natural surroundings near my home, the filter impressed me practically from the very first second.

The ability to work with considerable long exposures, even in the brightest lighting conditions, to achieve fantastic bokeh effects in my photos without having to adjust the aperture, is simply fantastic.

The only criticism I could offer is the previously mentioned lack of a filter stop for "minimum" and "maximum," in contrast to the filter's free, infinite 360° rotation. This means you always have to keep an eye on the ND ring to ensure it's in the correct position. But as I said, this is nitpicking at a very high level and doesn't warrant any deduction in points.

So, if you, like me, enjoy being outdoors and want to work with long exposure times even in bright daylight, you should definitely get this: a clear recommendation from me.

Visually, the item makes a very high-quality impression in its elegant packaging.

Simply put, you get two polarizing filters (PL) that can be rotated against each other, creating different and flexibly adjustable neutral density filters. These can be continuously adjusted from ND-2 to ND-400. A sturdy lever is attached to the side of the filter, allowing you to rotate the front part.

The rear part fits easily onto a camera filter thread without jamming, provided the environment is suitable. In dusty or sandy conditions, you need to be careful, as with any screw-in filter.

The price for a 77mm diameter filter is just under €100 without a discount. That's quite steep for a screw-in filter without a magnetic system. However, you only need to screw on one filter, and the darkening effect can be continuously adjusted, as mentioned, from ND-4 to ND-400. That's not a lot, but it's usually sufficient in practice.

Many camera systems max out at a shutter speed of 1/8000. However, if you want to achieve a shallow depth of field (smallest aperture/wide open) on a very bright sunny day and/or photograph flowing water, then neither the lowest possible ISO nor a short exposure time will help, because you want to achieve the opposite. This is where neutral density (ND) filters come into play, which are designed to darken the incoming light.

With this ND filter—as with all others that use this technology—two polarizing filters are simply rotated against each other. This reduces the amount of incoming light.

One thing to keep in mind with polarizing filters is that they also eliminate reflections from surfaces. This can be desirable, but also potentially undesirable.

Therefore, you need to carefully consider when using these flexible ND filters is worthwhile and when it's better to rely on conventional, simple ND filters. I would generally recommend magnetic filters here.

What I really like about the K&F Concept filter is the high-quality packaging and filter case. A small cord on the side makes it incredibly easy to remove the filter attachment from the small leather case.

Conclusion: Pricey but good

I initially gave it four stars, but then decided on five, as I didn't notice anything truly bothersome apart from the price.

That is, if you disregard a few minor things that can be used creatively, such as the blue tint to the light reflections when the filter is rotated beyond the N400 mark.

You wouldn't consider that a flaw in an anamorphic lens; it's simply part of the technology in some cases.

If you found this review helpful, please give it a like!

I don't have much experience with filters, nor do I have any to compare them to...

You can tell as soon as you open the box that this filter is in a different league.

The manufacturers haven't overdone it and everything looks very cohesive.

The lens case is clearly made of leather and has a magnetic closure.

I almost hesitate to pick up the lens itself, it feels so high-quality...

Screwing it on works perfectly, the fit is spot on, and adjusting the power has a pleasant resistance and is incredibly smooth!

In my opinion, the price of just under €78 is absolutely justified!