I tested the filter set for the Mini 4 Pro from K&F Concept as part of the Amazon Vine program and can now describe my experience with the product without any outside influence.

The six filters are delivered in a sturdy transport box made of light but durable plastic, measuring approx. 10.3 x 10.3 x 2 cm and thus significantly oversized. Unfortunately, I can no longer fit this filter box in my drone bag and I don't understand why K&F Concept wastes so much space. The foam padding is very high and thus protects the filters, but it also makes removing them a little fiddly.

The set includes the gray filters ND 4/8/16/32/64/1000. Due to the lighting conditions, I only tested the filters ND4/8/16/32. Since I use the drone a lot for taking photos, the ND1000 is actually never used, and the light has to be very bright for the ND64. Instead of ND 1000, a polarizing filter would be much more important to me. All filters are clearly marked with a print on the frame.

Mounting them on the Mini 4 Pro is easy and takes just a few seconds. However, I noticed that the filters do not sit quite as flush as filters from other third-party manufacturers that I have already tested. Nevertheless, all filters sit absolutely firmly on the gimbal and work perfectly on the drone. I could not detect any optical impairment.

The DJI Mini 4 Pro drone already takes really sharp pictures, but using ND filters makes the pictures even more effective. That's why I decided on the K&F set. The filters were delivered in a flat storage box, ideal for on the go.

Installation is easy, turn the frame slightly to the left, remove it and simply place the new filter on top, offset to the left, then turn it slightly to the right and it will be fixed in place. This makes changing it quickly possible. I generally use ND filters for photos and videos. I usually use ND16, ND32 and ND64 of these filters when the sun is shining during the day, and in winter when there is snow and a cloudless sky. From ND16, the filter softens the fast movements in video recordings, which comes across as silky. From ND128, you can create really great effect shots. It's best to try it out for yourself and then compare the results.

The quality of the materials, including the glass, the attachment is impeccable and the processing of the filters is flawless. It is quick and easy, they hold reliably, fit perfectly and the shots are even more professional. Another big advantage is that the lens is unprotected as standard, see photo where my finger is on the original lens attachment. It is just a frame without protective glass and with these filters everything is protected.

Explanation of the ND filter: I use them for long exposure and depending on the sunlight. This allows softer shots to be taken.

What is a gray filter/ND filter? A gray filter is a filter where the glass is darkened over the entire surface so that less light can penetrate the lens.

This makes it possible to choose longer shutter speeds and achieve the corresponding effects, such as misty water or soft, elongated clouds. This would not be possible without a filter.

About the gray filters:
Gray filters are available in different variations with slightly confusing names from suppliers. I don't want to go into the different manufacturers here, just the names. I had to work my way through them first, but basically it's easy to understand.

The information for this set means:
ND16 = slowing down the shutter speed by 4 f-stops to extend the exposure time
ND32 = slowing down the shutter speed by 5 f-stops to extend the exposure time
ND64 = slowing down the shutter speed by 6 f-stops to extend the exposure time
ND128 = slowing down the shutter speed by 7 f-stops to extend the exposure time
ND256 = slowing down the shutter speed by 8 f-stops to extend the exposure time
ND1000 = slowing down the shutter speed by 10 f-stops to extend the exposure time

This allows you to take pictures with more contrast and to make the most of the manual setting. When you use the different filters you will see how beneficial they really are. The price-performance ratio is top and the filters serve their purpose.

Thank you for taking the time to read my review. I hope I was able to help you a little with it, including the photos.

I ordered the set for my Mini 4 Pro. The ND filters are delivered in a relatively large plastic box, which could have been 1/3 smaller. You can just about fit the box in the side pocket of the original DJI bag.
The filters themselves are well made and hold well on the camera. Each one is labeled with the respective ND number on the edge.
I couldn't see any deterioration in quality in the first test shots.
Overall, I can recommend the filters.

I will use the filter to protect the camera lens on my drone.

My mini 4 pro does not have any coverage on the camera, with this filter I am more at peace without altering the images.

Nice build quality very good

good

This is a high quality tv filter/lenses protector that both helps eliminate glare and protect the camera lens. It succeeds in both counts. Seems highly oleophobic and at least reasonably scratch resistant.

Fits well. No complaints.

Does what it says. Adjustable polariser for the Mini 4 Pro. Case it comes in is quite large, but I leave the filter on my camera as protection for the camera lens.

I tried one other, did not get a good fit. It does exactly what a CPL should do, give good contrast enhancement and help saturate colors. It does also function as a small amount of ND to help in daytime video, about 1.5 stops. I like it and it is not too terribly overpriced as well.