Fits perfectly

Great filter up to 24mm with full frame, it's ok then you can see the edges, performance is excellent..

This K&F Concept 77mm UV filter is a good accessory for your expensive camera lenses. It protects the front element from dust and scratches - or in my case flying mud at motocross events. The filter fits easily on to all my 77mm filter threaded lenses, and comes with a centre release K&F lens cap too. The lens cap also has a cap keeper if you want to avoid loosing the lens cap.

What I like about this filter is the thickness - or lack of it - as it's 3mm thick and that means it doesn't appear to darken the corners of the frame even on the wide-angle lenses I tried. I used it on my 16-35mm lens and there was no visible vignetting with this filter, and that does happen with thicker filters. The multi-coating must be rather good too as I did not see any evidence of lens flare even without a lens hood and the sun in the edge of the frame.

The UV blocking capabilities are not needed these days for digital cameras as the image sensors have a UV filter on them, so you won't see a change in the colour cast as described in the product info.

The filter comes in a good protective box, and also includes a microfibre cleaning cloth.

For the price this is a good value lens protection filter.

I have this ultra-low reflection uv filter in three sizes! It is very well made, easily threads on the lens, and provides great UV protection as well as preventing my actual lens from being scratched. Great value for the price! Picture quality is great through the filter. I use this filter for everything outdoors.

up until now, square filter holders from other companies have been expensive, and we have endured with SIOTI holders.
I also had an old K&F holder, but it is difficult to use C-PL.
That's where this product comes in. I bought a set of holder + C-PL + ND1000 for the time being, but it is well thought out. There is no vignetting even at 16mm with the Nikkor16-35mmF4, and there is no annoying color cast.
I'm a little worried about the C-PL's adjustment dial squeaking, but I have no complaints at this price with this content.
After that, I would like to see a frame that can be attached to the existing filters sold on the overseas official site, and a filter case that can hold about 6 to 8 filters with the frame attached.
~Addition~
I purchased a 100x150 frame from the US site of K&F. Existing filters can now be used, and full-scale operation is now possible.

There are people that claims that when you use an UV filter on your lens, the resulting picture quality is degraded. Maybe my eyes are not that sharp but I cannot tell the difference. This one can be used to protect your lens from dust and the accidental touch with your fingertips. You can clean with included cloth or buy some of these wipes for lenses. Better destroy or damage this one and not your $2,500 lens.

I was very surprised and pleased with the quality and clarity of the Graduated Neutral Density filter. My only concern was the filter fit tighter than i thought necessary and I was afraid I might break it trying to insert it into the filter frame. A little lithium lube in the grooves of the frame helped. I’ve included two test photos I shot to show the effect of the filter. Obviously the one with the darker sky was the one with the filter while the other had no filter.

As with many K&F Concept products, the final quality is excellent. The special lens (UV) has an aluminum frame and fits the camera and feels the same as the original lens. It's reassuring to have an aftermarket product fitted that works as it should without putting you in situations where you need to be "careful".