haven't had a chance to do real tests yet, but I did take a few test shots in my garden to check for sharpness loss and color stem. I used a macro lens to check fine detail and a wide angle to see if it was consistent throughout the frame. I also compared it to my Lee Filters-sized stopper. I couldn't detect any significant loss of sharpness throughout the frame with either the macro or wide angle. There is a small color cast when looking at the exif data, but the in-camera shot has mostly adjusted it and can be edited manually if needed. Importantly, it seems to be consistent across the frame, even at 10mm on my apsc sensor. I've experienced the angling at wide angles (both 10mm and 22mm) but again it can be edited very quickly in Lightroom. It would have been nice if it came with a light gasket but for the massive difference in price compared to the bigger brands I can forgive them that. They can be purchased elsewhere online if needed, which I will do. Overall I'm pretty happy with it which is just as good as it made the slip through my Lee Filters binder when I wasn't paying attention and fell on the paving stones in my garden chipping the corners of the glass. That's my own fault though as it's a known issue I have with the holder, same issue with my Nisi filters in my holder so I think it's a bit worn out.

have a Sony A7iii and I was looking for a good adapter for my 2 Canon lenses, 85mm f/1.2 and 11-24mm wide angle lens. This K&F Concept Adapter fits my Sony A7iii well and supports the lenses. I was skeptical about the sharpness of the photos. However, this adapter really nails the sharpness. It's better not to use the widest aperture, because lenses from other manufacturers work extremely poorly. Both sample photos were taken with this adapter. The shot in Florida was taken with the wide-angle lens. The mountains are recorded with 85mm. Autofocus is excellent on a 7iii body, so I didn't see any significant difference between using the adapter and the native lens. Eyefocus works very well even in low light conditions. The good thing is that I was expecting a lot of vignette, but I was surprised to find out that this lens doesn't produce a large amount of vignette. So the bottom line is that you should give this adapter a try. It fits well, not too tight like some cheap adapters. The build quality is really good. Happy clicking!

The adapter works very well and all lenses from wide angle to tele and tamron to sigma worked with the camera without any problems. I even found the Canon EOS M's sluggish autofocus to be a little quicker. Now I can use my Canon 60D and the EOS M together without having to change lenses every time. Clear purchase recommendation.

Got the L/RL/M adapter to use a Leica R Macro lens on the Leica M for the few macro photos I take. I didn't feel like paying 160 EUR for an original Leica adapter, so I bought this one from K&F. R lens fits perfectly with no play, and the connection to the M camera is also perfect. It goes up and down nicely, without exerting any force, without anything wobbling. Perfect for my area of application. I've bought 3 K&F adapters so far and I'm super happy with them. They make a valuable, stable impression. It may be that after years they no longer have the quality of a Leica original due to larger manufacturing tolerances, but currently. it's great

The filter works best if you have a lens that is greater than 35mm. When the lens is too wide angle is when you get the X looking area

Got this to reduce overexposure with wide angle Canon 17-40 4L lens. Very happy with the results so far and it's really great for long exposures. I've been a K&F lens filter for a number of years and these have been my primary ND filters.

Hi use the filter on my wide angle lens. Unfortunately, at the max setting, a lens flare forms, which unfortunately doesn't look so great. At min setting it is ok (no lens flare) Processing is super. Unfortunately only conditionally usable. ML

I bought this ND filter for my wide angle lens and am very satisfied with one thing. The filter is well processed and makes a high-quality impression. But when the filter is on the lens, unfortunately the lens hood no longer fits on it because the front ring is slightly larger than the lens diameter. So far I could not see any color cast in the pictures I have taken so far.