Originally posted by sterretje Wouldn't that imply that you need 'excessive' force to mount them? If so, I indeed hope that they are cheap crap so the adapter gets damaged and not the mount on the camera
Excessive in what sense? Shiny surfaces + a bit of friction = difficulty mounting them manually.
The advantage of the third party adapters is that you can use them without that retainer clip, unlike the original ones.
If the adapter mounts easily with the key, mount it that way. If it feels like it requires excessive force with the key, then there is a problem.
Once you remove the retainer clip, you can also just screw it on a lens and try mounting it like that - but don't use a lot of force, just in case it is bad and it gets stuck.