I got the 77mm to fit my 24-70 f2.8 lens. This seems to be a really well made filter. Turning of the ND tabs is firm but butter smooth. Then you turn the whole outer frame housing for the polarizer adjustment. That is also firm, maaaybe just a little too firm as turning clockwise can actually start unscrewing the whole assembly from the lens! It does have a serrated inner lip to ease with tightening it to the lens.

Recommended!!

I am not a professional photographer but I do take a lot of pictures when I travel. Often I see something and have to reach into the camera bag, screw a filter on, and take the picture. This makes things a little more convenient. I can carry less filters when I travel since this single filter is adjustable and does the work of several filters.

This screwed flawlessly onto the end of my Canon lens. I like that I can simply dial in the filter setting that I need and I am ready to go in no time. I took several shots and I was totally pleased with the results.

This one will be in my lighter travel bag when I am out and about.

From the golden outer packaging comes a microfiber cloth wrapped in foil and the actual filter box. Inside is a filter that is oversized and heavy for the screw-in size. I have the filter in screw-in size 82mm and am testing it on the Leica Vario-Elmarit-SL 2.8/24-70 with the Leica SL2s.

The mount has a grooved grip ring for screwing in, which protrudes about 1 cm over the filter mount. This makes it easy to grip and screw in or out. There is no fiddling when changing the filter and no dealing with filter clamps when the filter is stuck! The manufacturing quality of the mount is excellent. The entire front frame of the filter has to be twisted to adjust the strength of the polarization. The screw-in knurled ring must be held in place because the rotation of the polarizing filter is difficult. The difficulty is not a design or manufacturing defect, but is for the 2nd function of the Filter is required, namely the darkening from factor 2 to 32, which is adjusted in the front part of the filter holder with 2 relatively large and easy-to-grip levers. If the polarizing filter adjustment were smoother, it would rotate with the ND adjustment.

The overhang of the filter holder makes a larger filter glass possible than with conventional screw-in filters, so that the thick filter does not vignette even at a 24mm focal length. The filter glass is visibly multi-layer coated; a water-repellent nano coating is applied to the front. The original lens cap can be snapped into the filter! All of this gives the impression of a very careful and well-considered design.

Polarizing and ND filters work as usual. There is no particular susceptibility to reflections and stray light. I cannot detect any impairment of the sharpness or an explicit color cast of the lenses. Of course, using the polarizing filter outdoors causes intentional color changes by filtering out the sky reflections, which means that, for example, green plants have a lower blue and a higher yellow component.

One basic problem with using the polarizing filter with mirrorless system cameras remains: except for reflections aimed at at an angle, the strength of the filter effect is practically undetectable on the OLED viewfinders. Landscape photographers who prefer polarizing filters are therefore recommended to use a DSLR with a mirror, in whose natural viewfinder image even small rotations of the polarizing filter are clearly visible. But this is not a fault of this filter, but rather affects polarizing filters in general.

Conclusion: A very carefully and practically constructed double filter at a very attractive price in comparison!

This K&F Concept 67mm Variable Fader ND and CPL Lens Filter is a really good, adaptable lens filter that combines two common lens filters into one with a variable adjustment. I was immediately impressed by how smooth the filter was. The adjustment itself is smooth and tight and the actual transition of the image is smooth to match it. The quality seems very good overall and it threaded smoothly onto my lens.

One note, I did not realize ahead of time is that you will need a different lens cap to fit on with the new filter. I have a 67mm lens and ordered the 67mm lens filter. My original lens cap does not fit on the new filter, so I now need a 72mm lens cap to go on this. There is a chart buried in the product description that shows the adapted lens cap size for each filter size but it is essentially a standard size up from whatever filter size you order. These are fairly inexpensive and easy to come by, but it would have been nice to include a corresponding lens cap with the product.

There are many applications where this comes in very handy and can allow you to get unique shots that would be difficult or impossible without this. Some applications would include scenarios like:
- mixed lighting conditions with bright and shadowed areas to balance the exposure;
- removing glare and reflections on reflective surfaces like water;
- landscape photography to reduce glare and improve the appearance of the sky; and
- taking long exposures in brighter conditions without overexposure.

The filter set to minimum does darken the image slightly. Also hoods and other accessories do not fit with this filter, so there are instances where you'll want this off the camera, such as low-light conditions. Still, this is a great all around filter that is worth having in your bag.

Overall I am very happy with the quality and function of this K&F Concept filter and would highly recommend it. Do keep in mind that you'll need a larger lens cap diameter than the size you order, but other than that I think this is a very worthwhile pick.

I am using this filter for outside shots on an IR converted Canon 40D with an internal 720nm filter. The CPL helps to make the open sky even darker, and the ND filter gives me the flexibility to do some cool shallow depth of field shots when close to wide open in sunlight. I had to use a 52mm to 55mm step-up converter to fit the Canon EF 50mm 1.8 II (nifty fifty) lens, but this setup matches the barrel diameter perfectly so it's not unwieldly.

I am an amateur photographer and in no way my opinion is professional. I have always been amazed by what filters can add to your photography game but the need to change between filters plus cost made trying them a challenge.

This filter seems to answer these concerns, it is multiple filters in one so no need to swap filters, just rotate to your choice.

The quality of the pictures is hard to judge since it is winter time and no sun light to filter, saying that however I don’t see any black crosses or distortions.

As for the price, it is reasonable. Almost the price of one filter.

this filter is super thick and yet light weight. very high quality. I love the dead stops on each side this prevents you from messing up your shot. the adjustments is nd 2-4-8-16-32.

I ordered this K&F Concept 82mm Variable Fader ND2-32 ND Filter and CPL Circular Polarizing Lens Filter to reduce the number of items I carry with me on a landscape shoot.

When shooting landscapes, a neutral density filter can come in handy. It's the easiest way to create that smooth water effect for waterfalls, rivers, and other moving water. And, a polarizing filter helps to tame reflections that would otherwise detract from your images. This filter from K&F combines these two types of filter into a single screw-on attachment.

I ordered this is the 82mm size (so that it would fit my largest lens) and I'll use step rings for smaller lenses. Operating is pretty easy. You use your fingers to rotate the CPL and you use the attached knows to rotate the variable ND filter. Based on meter readings, you'll get about a 6 stop reduction in exposure when the ND filter is set to max and the CPL is adjusted. With the ND set to minimum, you'll see about a stop and a half or so of exposure reduction.

I did not notice the X pattern that appears so frequently with variable ND filters. However, that tends to happen more with wide angle lenses, and a friend is using mine so I wasn't able to test that out. Color rendition is pretty neutral. I did not notice any reduction in sharpness, nor did I experience significant flaring. Unfortunately, it's not possible to use a lens hood when this filter is attached. Also, you need to know that the front diameter of the filter is greater than the rear diameter. For example, if you order the 82mm version of this filter, your 82mm lens cap will not fit. Instead, you'll need an 86mm lens cap. Be sure to look at the chart in the listing so that you know what specific size of lens cap you'll need for the filter size you purchase.

Great for video work, the ND filter slides from darkest to lightest smoothly and quietly. I do wish the ND numbers were on the filters instead of dots though, but other than that, it's really great.

Combining an ND filter and a Circular Polarizer in one filter is such a helpful filter, there's almost no reason to remove this from my lens, unless I am shooting indoors. Having both in one filter and being able to dial both in separately is such a good tool and accessory, it is really amazing for using when shooting outdoors in bright sunlight, for being able to lower the f-stop to get my aperture low and get those wonderfully creamy blurry backgrounds, and also dialing in the reflections off of the water, or enhancing the skies. This filter is quite a bit larger than most, and is definitely not a small thin filter, but the glass is great quality, and the threads are machined perfectly. I have no complaints about this filter at all and am really happy I decided to order it. It will get a lot of use from now on.