It is a very well-made adapter for attaching Canon EF/EF-S lenses to the Canon R system. All functions are transferred perfectly. The adapter sits perfectly and fits perfectly into the R system.
All photos were taken with the Canon R 7 in conjunction with a 100 mm macro from Canon.

This is a very well made adapter that mates smoothly and firmly between my old Pentax K lenses and my new Canon M50. It is completely passive with no glass or electronics. My 50mm 2.0 never looked so good. Multiply your lens focal length (mm) by 1.6 to get the effective length on the M50 cropped sensor (50mm = 80mm). NOTE: To use on the M50, you must enable Release Shutter Without Lens AND turn off the Lens abberation correction (both Peripheral illum and Chromatic aberr). If you forget to disable the correction, an "err 70" may occurr if you use the focus zoom aid function (magnifying glass) and you'll need to remove the camera battery to reset it. I've since turned the corrections back on and the issue has not happened again.

Ever since I switched from Canon DSLR to Fuji mirrorless, I have been unsure about what to do with my Canon gear. I invested so much in this brand, but the 5D Mark II was just not working anymore for my purposes, especially in low light and long exposure projects. I decided to order the auto focus mount adaptor from K&F and honestly did not have high expectations. These adaptors often don't fit precisely and are sometimes very hard to remove or install.
Well, today I took ALL of my Canon lenses out for a trip to test them with the adaptor on my Fuji X-t5. I am very impressed.
I used a wide angle, a medium wide-angle to medium close-up and the reason for buying the adaptor: my 200mm with 2x extender. The attached picture is taken out of hand at 400mm (200 with 2x extender) and it did a great job. It does even better on a tripod at this focal length but this bird was the true test, as it was not something I could prepare for. Had I come in with a tripod, it would have left. Now, all I did was lean against a tree for some basic support and this is what I got. This is a cropped and regularly sharpened image.
The miracle of this adaptor, that feel sturdy and has a smooth fit to the camera, is that it play really well with the Fuji body. I have full control over aperture and speed, I can use exposure correction and achieving focus was certainly acceptable. There were some situations where there was less contrast and it took a bit longer. But that is totally acceptable.
So, this is a good value for your buck - not just because it works as advertised, but mainly because it saves you a ton of dollars because there is no need to invest in a Fuji lens. My Canon gear now has retrieved its original value and more, because the Fuji body is such a top notch camera for my purposes.

This review is written right after buying the product. So if I find out that in time it operates less well, I will come back with a new review. For now I am very happy!

Great adapter, used to convert my vintage Pentax kit to the eos-m that I use as a backup camera.
I chose this brand instead of other more well-known ones to save a bit, but I was surprised by the build quality!
The adapter is all metal and adheres perfectly to both the camera body and the lenses, there are no differences in performance compared to more expensive adapters that I have also tried in the past.

I have tested it with light lenses (28mm f 3.5, 50 f1.7, 135 f2.8) and with much heavier lenses (for example the Pentax 70-210 f4 which weighs almost 1 kg) and it does not present strange play.

Highly recommended.

A good adapter with which I brought my “old” Pentax K lenses back to life on my Canon eos-M 3. Recommended

I had previously purchased several Canon EF lenses for my old and heavy EOS 5D mark ii. Having sold the 5D a decided to take a gamble and buy this converter. All my Canon lenses can now be attached to the Sony and the results are extremely good. Auto focus is fast, though it can struggle a little in low contrast situations. In such a situation it is easy to set to Manual focus. I've tested the following Canon lenses with great success.
EF 100mm f/2.8 macro
EF 50mm f/1.8 a cheap lens but really sharp results
EF 28-105mm f/3.5-4.5
EF 17-40mm f/4 L series
EF 24-105mm f/4 L series
Canon Extension Tube EF25 ii works too!
The only other slight negative is that the lens image stabilizer doesn't seem to work on those lenses that have it.
The other advantage is that there are lots of Canon lenses available in the second hand market. Why buy a new Sony lens when you can get good second hand Canon ones!
The picture was taken using the Canon 100mm macro lens hand held.

It works well, it allowed me to use my old Chinon (Pentax) lenses on the Canon EOS M50. It is quite solid, I obviously treat it with care.

I'm really happy with this adapter. I've used it on my Canon M50 with an old vintage Pentax mount lens and it works awesomely!

Have an old k-1000 35mm and it works great with my old manual lens on the Canon M series

K&F has created a very high quality lens, the materials are very good and resistant. I have tested it by mounting a Sigma 18-35 on a Canon EOS R series and it works wonderfully.