Nice quality with a solid built and it fits perfectly

This is a nice looking bit of kit, but its not the correct thickness. When measured flange to flange its 25.4mm but for old M42 full frame lenses to work on Micro Four Thirds it needs to be around 26.2. if you take the old full frame flange to sensor(film) distance of 45.46mm and subtract the MFT flange to sensor distance of 19.25mm you get the 26.2mm required. To get this adapter to work I had to unscrew the lens approximately 1.0mm to get infinity focus to the correct place which tally‘s with the maths.
This means when you set your manual lens to infinity focus you will get a blurry image. You will need to set your focus to 1.5 meters with a 35mm lens or 15 meters using a 135 mm lens to compensate or make some kind of packing washer to move the lens further away from your sensor.

Using the argument that it is designed to allow for lens tolerance is wrong, after all the old camera bodies worked fine. Plus camera bodies and lenses throughout the years were never manufactured to such sloppy tolerances. If this adapter was 26.1mm everything would be fine, the infinite focus would be so close to where it should be, as would all the other focus distances marked on the lens that there wouldn't be an issue.

Contrary to the experience of some others, I can find nothing but praise for this adapter.In use with an Olympus OMD E-M1 mark III and Canon FDn lenses, the adaptor has no play whatsoever on either camera body or lens, when mounted.
Before purchasing, I had watched several online videos explaining how to enable “off-camera” aperture adjustments on the FDn lenses, but have found that the easiest way to achieve this was to move the lens aperture control ring away from the green “A” setting and onto any actual f-stop setting, before taking the lens off the Canon camera body. (I am fortunate in still having a Canon A1 which enables me to do this).
Having done that, with the adapter then mounted onto the OMD body, and with its lock ring set to the “open” position, it is simply a matter of attaching the FDn lens to the adapter, and sliding the lock ring to the “lock” position.
That done, full manual aperture control of the lens becomes available by rotating the lens aperture ring to whichever aperture setting is required.
Note that although the E-M1 mark III body has inbuilt image stabilisation, in order to make the most of that facility, the camera needs to be “told” what focal length of Canon FDn lens is being used. (It is a simple matter to input that information via the OMD’s custom menu settings).
Enabling “focus-peaking” on the camera body makes fine control of manual focusing pretty much failsafe! (NB: I’m not sure if focus-peaking is available on all Olympus camera bodies).
Results thus far have been very good indeed, and have breathed a new and very useful life into my old FDn lenses. Exceptional results using my erstwhile “pride and joy” Canon FDn 85mm f1.2.
Well done to K&F Concept for making a good quality, easy to use adapter, at an affordable price!

I have used k&f before and the quality is good, but this k & f one with the Orange part is superior to whatever they build before. I woud buy this special adapter again and would recommend it.

This is one of the best adapters for using old M42 mount lenses on a Micro Four Thirds camera. Given the quality of a decent vintage M42 lenses, putting them on a decent adapter is a must. These adapters are fantastic and rarely even need to be adjusted for infinity.

Great product! Well built and a solid price for what you‘re getting.I bought this to attach my Sigma 75-300mm, I believe a vintage lens, to my micro four thirds Lumix G6 and it works great! Although now I'm only missing a lens ring mount as it is quite heave to be used on a tripod attached to the camera only!
Comes in a nice small plastic box, with bubble wrap of course, which is nice for display and storage. The adapter is easy to use, although remember to push the lock in when attaching your lenses!

Bought this lens to use my old Pentax lenses with my new digital camera. Found that the back focus with the adapter is incorrect, meaning that the lens does not focus correctly

I had two old lenses from a camera I bought around 1997, almost never used them. What a waste of money... until I recently bought an MFT camera and discovered you can use adapters like this one. Seems well made, feels robust, fits perfectly, looks nice and has a useful ring to change the aperture (note if you have an on-lens manual setting you may need to rotate the ring all the way to one side to stop it overriding the lens setting - not an issue just take note). Yes you do have to manually focus however if you are taking pictures of things that don‘t move too fast or if you are pick a point and get focussed before the action and have a small amount of patience that's easy. I have used my 300mm lens which provides excellent images. In the process of setting this up I have discovered two useful things (sorry - I am no photography expert so may seem obvious to those who are) first is that many cameras allow you to zoom into a very small bit of the photo which allows for easy manual focus (I expect this is common - my camera is around 9 years old - check your manual or Google it) second is that if using extreme levels of zoom and your camera relies on in-lens image stabilisation (like mine) then you might struggle with an old manual lens to get a crisp image, if you do then choose a large aperture (small f number I believe - allowing in plenty of light so you can have faster shutter speeds - also producing really nice shallow depth of field - for dummies like me that means a clear subject and soft focus for the rest of the image) and/or use the sport mode on your camera... it's worked a treat for me. Real photographers - apologies for the really basic explanation - however it has worked for me. Happy snapping!
Edit - still using it and still working great. Have bought a few cheap old lenses and great fun to be able to use them with the MFT camera. No idea why people have scored this 1 star unless they think their autofocus will still work with one of these!

Got this adapter to go from a Pentax 50mm 1.4 to the GH5 and it works really well. It‘s really well built and the aperture control ring is a nice touch. Would definitely recommend.

Pretty simple product that does the job of adapting Minolta lenses to work on Sony e-mount cameras. If you're looking to do that sort of thing, this adapter is a great choice! Feels like a quality product that should last for a very long time.