I had been meaning to buy a variable ND filter for my 24-70f2.8l for a while. When I heard about K&F filters; having tried a 3xnd filter kit pack that I was impressed with; especially at the price. I looked at K&F's other products and found this more than reasonable price ND filter and had to give it a go.

The filter is shipped from China; so its not something to order if you are in a rush - but when it did arrive I was blown away by the quality of the presentation. The filter was packaged inside a well designed; expensive looking, cardboard outer package and then a hard plastic inner with a foam sheet to allow it some protection.

On opening the pack one disadvantage to this filter immediately manifested itself; the front element isn't 77mm so your lens cap won't go back on the lens with the filter mounted. The filter mounted smoothly onto my lens. The variable darkness is achieved by rotating the front element; as you would a circular polariser. The K&F filter spun smoothly but with enough resistance to keep the darkness you set so knocking it won't change the setting. One disadvantage to the design is the filter doesn't have coded ND values so there is a bit of guesswork to get the right exposure for stills.

I tried the obvious and took an image of a plain white wall at various ND settings; and there was some minor differences in the brightness of the photo - it was a bit lighter at the edges of the frames. At its darkest on long exposures; the 6d went red shift but this is correctable in Lightroom (and made much easier if you use a colour checker passport.) If you zoomed in on the plane white background you could see some variations in darkness; and ultimately pixel peeping at maximum darkness a mesh. That said taking pictures of something more interesting than a wall the effect was lost in the detail of the image.

I rarely shoot video so for you dear reviewer; I shot some test video of the same white wall. I don't have any fancy video editing software and just watching the video back in lightroom; the darkening effect was pretty uniform across the photo. As with stills if there were any criticism it is very minor and that the corners show up brighter than the centre of the frame. The majority of the frame being uniformly dark. There was no patterning showing in the video.

Using a standard ND filter definitely gave a more even darkness to stills but I am planning 3 long trips this year and carrying 5 ND filters everywhere felt like a chore. Now I just need one. If i could I would ding 1/2 a star for the front element size not being 77mm but its a minor inconvenience in the scheme of things.

Full disclosure: I received this filter system at a significantly reduced cost in return for my unbiased review.

I just purchased a new Canon RF 100-400 lens that has pretty good glass but is not L quality. Although I have a good black and white CPL filter that matches this lens, I have never been very happy with the color cast. I have tried other K&F Concept lenses and was very impressed with the neutral color cast. So I decided to give this polarizer kit a try.

I really like the technology in this kit. This kit comes as a compact sandwich with machined metal caps front and back. All caps and filters are clearly marked with the filter size. There is a small storage bag to protect the filters and your other stuff when you throw them in your bag.

I previously tried another K & F filter and while I was very impressed with the glass, I was much less impressed with the machined aluminum frame. Unlike the previous filters, these attach easily to my lenses and don't bind. In practice, the knurling on the filters makes removal very easy and in the case of the CPL, the adjustment is very smooth. There is noticeable resistance, but no hint of binding or freedom of movement that you get with cheaper filters. The feel of this filter is quite nice.

The thin profile UV filter is MRC coated to reduce glare and improve cleaning. This filter produces virtually no color cast at all. When held up to a white background, I can't tell the difference between filtered and unfiltered white. I don't usually use UV filters because most of my lenses have better front elements than any filter I own, but with the RF100-400, I'll probably leave the UV filter on the lens since it doesn't have the same quality coatings as my other lenses.

The CPL is fairly thick, but not so thick that I will worry about vignetting since I use these mostly with medium to long telephoto lenses. All CPLs affect color to some degree. Depending on the polarization and angle of the sun, they usually darken the sky and change the color of the water, sometimes dramatically, so with a CPL it is difficult to determine what color cast may be present. Using the same test on a white background, I can see a slight cast against the adjacent white background that seems to have a somewhat brownish cast, but could simply be the result of light loss from the CPL. In test photos, I could not see any perceptible cast at all. It's close enough to neutral that I don't think it will have much effect on color correction in post.

All in all, really nice filters and pretty good value for the money. Recommended.

The pictures are clear and amazing, I love this camera, the black and white is amazing, color is vivid, I recommend this camera to all.

I chose the surveillance camera for outdoor use.

The total package comes with everything you need. Installation material is included. Everything is also included for wall mounting. Once everything is done, the app is installed.

Once the app is installed, you have to register. You also have to enter your e-mail address to receive the confirmation code.

The app is easy to understand. The camera records small video sequences when movements are made. It is also recorded more often, although you do not see any recognizable movement. Fortunately, this can be deleted again. The intercom works quite well so far.

The transmission during the day is crystal clear. But if the recording is not so good, the picture is shown only in black and white. At night, you can choose between color and black and white.

I chose the outdoor security camera.

The complete package comes with everything you need. Installation material is included. Everything is included for wall mounting. Once you've done everything, it's time to install the app.

Once the app is installed, you have to register. You also have to enter your e-mail address in order to receive the confirmation code.

The app is easy to understand. When there is movement, the camera records small video sequences. It is also often recorded, although you can't see any recognizable movement. Luckily it can be deleted. The intercom has worked quite well so far.

Transmission during the day is crystal clear. However, if the recording is not that good, the picture is only shown in black and white. At night you can choose between color and black and white.

The main piece is a diffuser/scrim, which has the hoop. The other modifiers --black, white, silver, and gold--are the surfaces of zip-on attachment. The photos in the description make it look like you're getting five different pieces. This is not true.

The fit and finish seem to be okay. My worry is that the hoop has a bit of a hard edge, which would make it easier to wear through the fabric holding the scrim on. Would have liked to see some padding or heavier-duty fabric at these wear points. The modifiers come with white and gold on the outside. The silver and black come on the inside, so when you want to use the silver modifier, you have to take the pouch off and turn it inside out. This is a royal pain. I'm probably going to leave the black/silver on the outside. The scrim is probably enough to use as a white reflector. I've taken to folding only the scrim to put in the carrying case, folding the modifier pouch separately, and storing that in the case.

I like the idea, but the implementation is lacking IMHO.

Diffusion filters like this one come in black and white. I like to call the white ones “bottom-up” diffusers. They increase the brightness of shadows as they diffuse. A black diffuser is a top-down diffuser that slightly reduces highlights while softening the image. Matches my Canon L series lenses perfectly and as a diffusion effect it offers good image quality at a good price. In fact, where some types of filters are worth paying the premium, a diffusion filter is a place to save a little money if you can. Since the effect itself essentially degrades the image to create a creative effect, as long as the creative effect looks good, you'll get your money's worth. Five stars.

Diffusion filters like this come in "black" and "white." The white ones I like to call "bottom up" diffusors. They increase the brightness of the shadows as they diffuse.

A black diffuser is a "top down" diffuser, taking the highlights down slightly while softening the image.

Fits my Canon L-series lenses perfectly, and as a diffusion effect, gives nice image quality at a good price. In fact, where some types of filters are worth paying the premium, a diffusion filter is a place to save a little cash when you can. Since the effect itself essentially degrades the image to get a creative effect, so long as the creative effect looks good, you're getting your money's worth.

Five stars.