have an EOS 350D available on which I want to test the use of my Nikkor AI lenses. I received the adapter ring today and tried it out right away. The processing of the adapter ring is very good, the connection to the camera works perfectly. Since there is no description, you first have to think about the correct attachment to the lens (description below). When this is done, the ring can be put on and fastened (relatively stiff). Detaching the ring from the lens is also relatively difficult, not at all for me at first until I found the right procedure and "practiced". A point is deducted for the missing description. All in all, a recommendable adapter. It remains to be seen whether the problems identified so far with the EOS can be solved with connected AI lenses. Description of connection/dismantling of the adapter lens: Set the maximum f-number on the lens. Position the adapter with its red dot opposite the black dot on the lens. Fasten anti-clockwise (movable pin of the adapter goes into the U-groove of the bayonet ring). This also ensures that the lens is correctly aligned when the adapter is connected to the camera (aperture and distance settings visible from above). To disassemble the adapter, hold the aperture ring with one hand and use the index finger of the other hand to press down on the small release lever while turning the other fingers clockwise to release the adapter from the lens.

The M42 - EOS EF adapter does exactly what it should. It fits perfectly on my Jupiter-9 85/2 lens. Everything is tight and nothing wobbles. The packaging and processing of the adapter is excellent. For info. The standard M42 Russian lenses, which were copied from the 50s to the 90s, often have a back focus of 45.5mm. An EOS camera has a back focus of 44mm. The adapter has a thickness of 1.4mm (measured). That means I get a total distance of 45.4mm. Theoretically, 0.1mm is still missing, but with the focus in infinity it still works. Most old optics are used for portrait photography anyway.

I bought it to mount Nikon F mount lenses on a Canon 5D Mark IV and III body and it fits perfectly with zero slack. As these are manual lenses, there is obviously no autofocus and the diaphragm is closed manually.

If they added a tab that closed and opened the diaphragm it would be 100% perfect.

The product meets my needs to serve as an adapter from a Nikon lens to my Canon camera. The only problem has been that I had to do a lot of research to make sure the lens worked. In the product description they are not too specific. Otherwise perfect and received within 12 hours of ordering

I wish the lens release knob was easier to access without taking off the mount form the camera side.

Great quality product, still did not brake.

Fits really well, creates a nice solid mount with little to no loose connection ensuring focus pulling is never shakey

very good the AI and AI-S lenses works very well this adapter is very well made solid, good job very happy this product it very good solid and smooth I am very happy

Adapter is solid and well made. I love the button on the back for removing the ring off a lens. It's much easier to use than the metal tab some other adapters have. The only small inconvenience is not being able to switch lenses on the camera without having to remove the adapter as well, but the button allows for switching lenses relatively quickly without much fiddling.

This is a great mount for lenses that have a built-in manual aperture adjustment, not the best for AF lenses.