I tested the K&F Concept filters on a Canon EOS 5D Mark III with a Canon lens.
I am very satisfied.

The filters are very well made. They are delivered well packaged. It is also practical that you get them right away in a well-padded bag and can thus store them well protected in the photo backpack. So the filters can also get no scratches and you always have the filters of one size together.

Also supplied is a cleaning brush.

The filters are absolutely accurate fit. This is not self-evident for filters of this price category.
I received the filters on a test basis which has no influence on my rating.

Original photos

The filter works very well on my Sony Alpha 7 III with a Tamron 24mm F / 2.8. There is no cross formation or other unsightly effects. The workmanship feels good and comes in a practical plastic case. As always, the shipping was great with Amazon. I can definitely recommend the 67mm version of the filter. BUT, the filter may not take into account that well in other sizes.

I bought the K&F Mark CPL filter holder as a replacement for the MK 2, which was quite cumbersome to remove and install the polarizing filter. The magnetic polarizing filter is now easier to change.

There are 5 stars for the entire system due to the good price/performance ratio.

I ordered this filter for my Canon M50 Mark II lens and it fits like a glove. The material of the filter is metal and robust. The coating on the lens ensures more realistic colors. I recommend it as an addition to your camera equipment.

It works great and allows you to auto focus with the old wonderful Zuiko on the Sony A7 III!

In perfect condition. I fit great with my Canon Mark II. The focus is on the hand

use the following other lenses on my Sony A7 Mark III: 24 - 105mm 4.0 | 16 - 35mm 4.0 | 85mm 1.8 | Just so you have references for my review...I think the lenses I listed above are beyond reproach. I was skeptical about the Samyang at first. I bought the lens because I ... a) wanted a light fixed focal length that forces me to use this really "cool" 35mm;-) b) wanted a light combination c) I'm still relatively flexible with it ("Street " not necessarily only people, but in the city) possibly also portraits (not classic, just more reportage) ... the fixed focal length should of course be quite sharp (but sharpness is really not the most important thing for me when taking photos, just a side note) d) Face detection and eye autofocus would be very nice because then I can focus on composition The Samyang really has all of those things. That's a really good lens! It is of course a value for money monster! The only downside... no metal, but plastic. But I can do without it. It would be "stupid" the other way around. Metal and for that a cucumber of lens, right? Here you can really access without hesitation. It's a lot of fun, the autofocus works really surprisingly well...I wasn't really expecting it.

Use this on my Sony A7 III and I'm thrilled. Darks really great without discoloration etc.