Square Blue Streak Filter 4'' x 5.65'' Cinema Filter Compatible with Tilta Compatible with SmallRig and Other Matte Box, 4mm Slim/HD Optical Glass/Multi Layer Coating

The K&F Concept 4'' x 5.65'' Square ND1.5 (5 Stops) Filter delivers excellent optical quality with no observable coloration, making it perfect for high-clarity pictures in both 4K and 8K video shooting. The included carry case is great too, making it a top choice for photographers and videographers alike. Overall, it's a stellar product deserving of its 5-star rating.

I'm gradually getting into matte boxes and square filters such as this. I've had great experience with K&F's circular filters that thread onto the front of my lens, and this square filter by them meets my continued expectation of excellent quality from K&F. It fits well, albeit tightly, in my Neewer matte box, though I believe this is more on Neewer's side than K&F's side. The 3-stop ND filter works great. I don't notice any significant color change. Obviously, there's no X issue as it isn't a variable. I love it. Carrying a square filter around is much more cumbersome than a round filter, but it's a learning experience.

Most of the Square style ND filters are so expensive, but K&F's new line are very affordable. The glass quality is just as good as those that costs a few hundred dollars. It comes with a storage pouch, which feels very high quality, and provides very good protection when storing it in the bag. I am totally loving it, and would get it again.

The filter is top notch and will work in most any standard matte box.
I use it to shoot landscapes (morning time), but this really shines for shooting video.
The filter works as advertised and gives a buttery smooth diffusion with just the right touch.
This will save a lot of post processing in both stills and video.
Now the presentation of this filter is out of the park great...really nice visually and tactile.
K&F are trying to make an impression with this filter, and it shows in the packaging and storage.
You can 'lift' the glass filter out of the pouch by just pulling on the heavy cotton red ribbon.
The filter is lifted up more than enough for you to grab the filter by the edges.
It's such an elegant solution.
The storage container is made of leather with two tones.
Like I said, they want this to stand out, and it does.
If you shoot a lot of video, you probably need a good mild diffuser.
If you need a good mild diffuser...you might as well get this one.

Top notch!

Never heard of this company before, so took a chance, as square filters are usually expensive, and this was in the ballpark of a decent price. The glass is well made and had no peeling. Have ran a few test shots with decent to good results, but not extensively on a long term shoot yet.

For the price it works. 5 stops is plenty and a good starting point for ND filters, especially with cinema cams. I use this with a Black Magic Pocket 4K and tilta matte box.

This is a perfect fit for my smallrig matte box and I was incredibly impressed with the quality of the packaging. The filter comes in its own, faux leather case with magnetic closure. When opening the case it pulls up on a ribbon that goes under the filter making it so that it pulls the filter up high enough to get your fingers on the edges without needing to touch the surface of the glass. I have checked it for a color cast yet, so I can't speak to that, but so far I'm very pleased with it.

Very exquisitely packaged, luxurious leather pouch containing the soft packing paper-wrapped optical glass. You definitely get what you pay for.

The close-up photo doesn't really do justice for the optical filter glass, as I have a colored curtain putting a tinge on that photo. The greenish hue on the product photos was a little concerning too. But the glass itself is properly neutral and clear aside from the evenly spread black specks that blur out into the intentional diffusion effect on photos.

It's not for the faint-hearted, just-to-try kind of photography, and won't really work with casual phone-based photographers, as your phone will tend to automatically remove the effect as if there wasn't a filter in first place.
It's a proper enthusiast -> professional photographer filter for the intended and desired effect.

At about 4mm thick, with its measurements of 4” x 5.65”, the K&F Concept UV Cinema Filter is a pretty hefty chunk of glass, and with all those coatings, on both sides, a beautiful thing to behold. A UV filter is generally used to, you guessed it, block UV light from a light sensitive material, and very often as inexpensive insurance to protect the front element of expensive lenses.

I have a number of K&F Concept filters, most of my lenses live their lives with a K&F protective filter on their front element. I also own some of their other photo/video accessories as well; I consider them a trusted manufacturer.

As the seller asserts, their Cinema Filter is sized specifically for Tilta and Smallrig mini matt boxes, although there may be other manufacturers that I’m not aware of. A matt box, that fits onto the front of a lens, is basically used for two purposes, as a filter holder and a lens shade. In the case of the Tilta MB-T15 matt box I use, there are grooves on the leading edge into which the filter slides and is held snuggly in place.

Handling the filter takes some care, since it is not enclosed in anything, for example a frame, but is glass from edge to edge. In our case, we keep cotton gloves around for such situations, and use them when handling the filter. Oddly, K&F Concept has always provided a cleaning cloth with every other filter I’ve acquired from them, but not in this case; it would be nice if they did, but I’m not complaining.

The filter arrives in retail packaging, with a magnetic closure, that is a storage case unto itself, however the actual filter case, that gives the impression of faux leather, is exceptional. It has a flip open flap with a bright orange nylon strap attached that when pulled, slides the filter up and out, making it convenient to grasp from the edges. The inner lining of the filter case appears to be soft cotton, although I am not certain of that.

I ran three tests with the filter: one to check its exposure accuracy, another to check whether it diminishes the sharpness of the transmitted image, and a third to check the effectiveness of its UV blocking. I included results for each.

For the exposure and sharpness tests, I photographed the lettering on the back of a box of cake mix, under artificial light. In the case of the exposure test, I simply calculated the exposure with the UV filter applied, and made the exposure. I then removed the filter, and made another exposure without changing the camera settings. I found that the filter has no significant effect on exposure; both exposures were recorded with the histogram in the same range.

For the sharpness test, I used the same two images, with and without the filter, and enlarged them 500%. In this case, again, I found that the filter did not diminish sharpness to any significant degree, which is surprising given the thickness of the glass. I provided the pictures and labelled them.

To test the filters UV effect, I shot the same outdoor scene, at the same camera settings, with and without the filter. To my eye, it may have reduced UV a tiny bit, but not enough to matter. That said, modern digital sensors, unaltered, record the entire spectrum of visible light, as well as most of the spectrum of infrared and ultraviolet light. In order to record only visible light, manufacturers install what is called an IR Cut Hot Mirror filter over the digital sensor and its Bayer Array of most off-the-shelf digital cameras. Digital cameras sold without this filter are referred to as a “Full Spectrum Camera.” If you’re not sure whether your camera is full spectrum or not, it isn’t; full spectrum cameras produce a result similar to that of infrared film.

UV filters are effective when recording on film, but have little added effect when capturing with a digital sensor that already has a UV filter installed by the manufacturer. In the case of my digital imaging, I use UV filters to protect the front element of expensive lenses. And in that respect, the K&F Concept Cinema UV Filter can provide the same protection for expensive cinema lenses without impacting camera settings, in effect providing relatively inexpensive insurance.

The physical quality of the K&F Concept ND Cinema Filter, and its coatings, along with the provided case, appear outstanding. I’m looking forward to using the filter in a live shooting situation.

At about 4mm thick, with its measurements of 4” x 5.65”, the K&F Concept 0.9 ND Cinema Filter is a pretty hefty chunk of glass, and with all those coatings, on both sides, a beautiful thing to behold. A 0.9 ND filter is used to reduce transmitted light by 3-stops, allowing the user more options and better control of exposure in brightly lit environments.

I have a number of K&F Concept filters, most of my lenses live their lives with a K&F protective filter on their front element, and I own some of their other photo/video accessories as well; I consider them a trusted manufacturer.

As the seller asserts, their Cinema Filter is sized specifically for Tilta and Smallrig mini matt boxes, although there may be other manufacturer’s matt boxes that they fit. A matt box fits onto the front of a lens, basically serving two purposes, as a filter holder and a lens shade. In the case of the Tilta matt box, there are grooves on the leading edge into which the filter slides and is held snuggly in place.

Handling the filter takes some care, since it is not enclosed in anything, for example a frame, but is glass from edge to edge. In our case, we keep cotton gloves around for such situations, and use them when handling the filter. Oddly, K&F Concept has always provided a cleaning cloth with every other filter I’ve acquired from them, but not in this case; it would be nice if they did, but I’m not complaining.

The filter arrives in retail packaging, with a magnetic closure, that is a storage case unto itself, however the actual filter case, that gives the impression of faux leather, is exceptional. It has a flip open flap (a flipping-flap) with a bright orange nylon strap attached that when pulled, slides the filter up and out, making it convenient to grasp from the edges. The inner lining of the filter case appears to be soft cotton, although I am not certain of that.

I ran a couple of tests on the filter, one to check its exposure accuracy and another to check whether it diminishes the sharpness of the transmitted image. For those tests, the results of which I have provided, I photographed the lettering on the back of a box of cake mix, under artificial light. In the case of the exposure test, I simply calculated the exposure with the ND filter applied, and made the exposure. I then removed the filter, closed down three stops, since I am testing an ND 0.9 filter, and made another exposure. I found the seller’s stated filter factor of 0.9 to be accurate; both exposures were recorded with the histogram in the same range.

For the sharpness test, I used the same two images, with and without the filter, and enlarged them 500%. In this case, I found that the filter did have the effect of diminishing the sharpness. I provided the pictures and labelled them. This may not be an issue if you aren’t enlarging your videos significantly.

The physical quality of the K&F Concept ND Cinema Filter, and its coatings, along with the provided case, appear outstanding. The filter factor of 0.9 is accurate as far as my testing determined, but I am disappointed in the reduction of sharpness. That said, that may not be an issue in practice, since, in my opinion, modern digital video capture is overly sharp and unemotional anyway. I’ll know more when I’ve had a chance to use the lens in a live shooting situation.

I mostly shoot with spherical lenses, so thought this might be fun to get those anamorphic style flares from hard light sources.

My first impression upon opening are really good. The leather-like pouch feels really nice and has a very useful pull tab that lifts the filter up out of the pouch so you can grab it without getting fingerprints on the faces. I wish more filter pouches used a similar setup. The 4x5.65" filter is a standard in the cinema industry and fits in perfectly with my filter kit and is properly sized for a standard matte box tray.

I took a couple photos with my phone that demonstrate how the filter works. As you can see, harder light sources add that traditional blue anamorphic streak across the frame. I feel like blue is very sci-fi and works well in those scenarios, as well as some music videos. It's a bit intense for general use, in my opinion, but for a filter this cheap, it's worth having in my kit for those infrequent times I want to get this specific look. Usually streak filters like this are far more expensive, but this has similar results to those higher priced options.

I've been quite happy with my assortment of K&F filters and feel like they punch way above their price point, competing with filters much more expensive. This is yet another perfect example of K&F doing it right and saving me a bunch of money. Would recommend.