K&F Concept Filters Review: A Hands-On Test of 4 Filters

By: Christina N Dickson on May 7, 2024

This article was updated in May 2024 with contributions from Kav Dadfar and Jaymes Dempsey.

I’ve long been an advocate of carrying as little camera equipment as possible. In fact, most other photographers are surprised to hear how little I carry with me on any trip.

Besides the extra weight, carrying more gear means you have more things to lose or have stolen. But while carrying less is always better – in my opinion, anyway! – there are some things I simply can’t live without. Filters are one type of accessory that I always take with me, as they’re essential for my photography. So when I was sent four new K&F Concept filters, I was very excited to put them to the test.

Here are the K&F Concept filters that I review below:

I display test shots for each of the filters I tried, and I offer my thoughts on the performance of each model.

Note: K&F Concept sent me these filters free of charge. However, I am not paid or affiliated with K&F Concept, and my review is honest and based on my personal experience using the products!

Why should you use filters?

As advanced as digital cameras are these days, they still occasionally need some help to capture photos the way you want, especially if you’re a landscape, cityscape, or outdoor portrait photographer. Often the big issue in photography is light. Too much of it, not enough, too harsh, in the wrong place – if only you could control outdoor light like in a studio!

Filters can help a photographer control light in varied circumstances. There are lots of filters that satisfy different needs. Two of the most common filters in use today are neutral density filters and polarizing filters.

Polarizing filters

Polarizing filters help remove unwanted reflections. For example, if you are photographing water or through glass, they’ll reduce reflections so you can capture the subjects behind the reflective surface. In addition to reducing reflections, they also boost color saturation (especially blues and greens). So they’re great for photographing popular landscape subjects, such as waterfalls, beaches, lakes, and rivers.

Neutral density filters

Neutral density filters reduce the amount of light that enters the lens. This allows you to select a shutter speed that’s slower than usual.

ND filters are commonly used to create motion blur in the landscape – such as when photographing water during the day or moving clouds.

However, even in day-to-day photography, ND filters can be useful to help avoid overexposure at wide apertures. Outdoor portrait photographers sometimes carry ND filters for this exact reason.

Square filters vs screw-on filters

There are two types of filters these days: square filters and screw-on filters.

Square filters are square or rectangular pieces of glass (or plastic) that attach to your lens by way of a holder.

K&F Concept filter review — A square filter mounts to your lens via a filter holder. Note the brackets on the front of my lens.

As the name suggests, screw-on filters screw onto your lens directly (i.e., no holder is necessary).

There are pros and cons for using both, and certain types of filters are commonly found in one configuration. I have always used square filters, but the K&F Concept filters that I tested were all screw-on, so it was a chance for me to experience something new.

The K&F Concept filters that I reviewed

As I noted in the introduction, I reviewed these K&F Concept filters:

K&F Concept offers plenty of other options, but these four filters provide a nice overview of the company’s filter selection. I was able to test circular polarizers and neutral density filters to give you a sense of whether K&F Concept’s filter lineup is worth considering.

Note that I tested the 77mm version of these filters simply because I was using a lens with a 77mm filter thread. If you purchase any of the filters I discuss, make sure you match the filter size to your lens’s thread, not mine; otherwise, you’ll find that the filters don’t screw onto your lens. K&F Concept offers each filter in various sizes, and the performance is identical from size to size, so my review of the filters will remain relevant regardless of your lens size.

Packaging and unboxing

My first impression of the filters was of the beautiful and secure packaging in which they arrived. K&F Concept packages each filter in a hard cardboard box, with each filter placed in a hard plastic case inside the cardboard box. Each filter is further protected inside the plastic box because it’s wrapped in a plastic bag and placed on a piece of foam.

The plastic box makes the filters extremely accessible when needed, as the lid flips open. The circular polarizing filter comes in a slightly different plastic box – it twists open rather than flips – but it’s still secure inside due to some rubber ridges. This stops the filter from rattling around in the case.

I will need to stick some small stickers on the plastic boxes and write the filter name on them to make them easier to find; this is currently lacking on the plastic boxes. Other than that, the packing is very impressive.

Build and ease of use

With the exception of the circular polarizer filter, the filter frames are made from an aluminum alloy. (The polarizer filter frame is made from extra-tough magnalium). Even though the frames are very slim in design, they certainly feel rigid, and I noticed no real bending even when I tried to force them.

All the filters are made from coated optical glass that is designed to reduce reflections. It’s also waterproof and scratch-resistant, which is always helpful for outdoor photography where you never quite know what you’ll encounter!

Bottom line: The filters are highly durable and should serve you well, even if you shoot in fairly rough environments.

Filter performance

As someone who has always used square filters, I was skeptical about the quality of these screw-on filters. I was worried they would affect image quality by producing vignettes or color casts – this is a common problem when using cheaper filters – so I was determined to conduct rigorous tests.

I deliberately headed out during the early afternoon as I wanted to evaluate these filters in harsh light. Below, I share my sample images and my thoughts on the performance of each model.

Testing the K&F Concept Circular Polarizer

I conducted my first test with the 77mm Circular Polarizer filter. Below are two images taken from the same place only seconds apart. The image on the left was captured with no filter. Then I placed the filter onto my lens to capture the image on the right:

Note the reflections in the water in the unfiltered shot; in the polarized image, the reflections are almost completely gone, allowing you to see the rocks on the riverbed.

If you look carefully, you can see that the blue in the sky was subtly boosted by the polarizing filter. There is a very slight vignette in the top left corner, but this is so minor that it can easily be removed in post-production.

Testing the K&F Concept ND2-ND32 Variable Neutral Density filter

I conducted the next test with the 77mm ND2-ND32 Variable Neutral Density filter. It screwed in easily and was easy to remove without any jamming.

This filter is a variable ND model, so by rotating the front of the filter, you can get different light-blocking intensities. Therefore, it was important to test the filter at a variety of strengths. As you can see from my sample images below, the ND filter performed very well across the board, with no color casts or vignetting.

I also didn’t come across the X-cross issue – where an X-shaped vignette appears across the frame – that sometimes occurs with variable ND filters.

Testing the K&F Concept ND8-ND128 Variable Neutral Density filter

The 77mm ND2-ND32 Variable Neutral Density filter was also easy to screw on and remove from my lens, and it performed well, too:

Vignetting was kept to a minimum, there was no X-cross, and the image colors were natural.

The thing that I found so useful with these variable filters is the ease of transporting them and the amount of space saved in my camera bag. To be able to carry two ND filters that cover such a wide range is definitely a huge benefit!

Testing the K&F Concept ND2-ND32 Variable Neutral Density and Circular Polarizing filter

The final filter tested was the 77mm ND2-ND32 Variable Neutral Density and Circular Polarizing filter. While I was impressed with the other filters, this is the one that I really found useful.

If I need to shoot with an ND filter and a polarizer, I normally screw on my circular polarizing filter, then screw on my filter holder ring, put the holder on, and add the filters I need before I’m ready to shoot. It’s a time-consuming process, and it’s one that I’d prefer to avoid.

Fortunately, this K&F Concept filter does it all! It works as a polarizer and as a variable ND filter, so instead of mounting multiple filters to the front of my lens, I can just add one. You can see below how using the filter gave me a longer shutter speed to achieve smooth water – even in relatively bright light – and also removed much of the water reflection. This helped bring out the details on the riverbed.

K&F Concept filters: verdict

As mentioned, I have always been skeptical of using circular or screw-in filters. However, I am thoroughly impressed with the K&F Concept filters I reviewed. The image quality is superb and the added benefit of just using one variable ND filter and adjusting the gradient without having to stack filters is really useful.

The thing that I really loved about these filters is how premium they look, feel, and perform. In fact, I didn’t notice any difference between these K&F Concept filters and my (much more expensive) square filters.

Another huge benefit of these filters is the cost. At the time of writing, the 5-stop variable ND and CPL filter is priced around $90. And you get six filters for that price! Individually purchasing high-quality filters will be a lot more expensive. This will obviously help anyone starting out and wanting to build their accessories up without spending a small fortune. I, for one, will be adding these filters to my collection!