When I put the adapter I just got on to my Nikkors and Nikons, it moves just a bit on the lens. Is this common or acceptable. I think I can live with it unless there is a reason to consider this unacceptable. I think I have read about it before but have not determined what is the consensus on this? It is a "Flashpoint" Nikon-Canon from adorama.com

I have the KAWA brand adapter. When I first installed it on the lens (Nikkor 80-200mm f2.8 push-pull), it was very tight and secure against the EOS body. After a few weeks of using the lens for general photography, I've noticed that it will torque slightly left and right against the mount when I focus. This is a pretty heavy, brass construction, zoom lens. I can live with this small amount of play given the circumstances, and the fact that the adapter was about $10US.
I would suspect that on a smaller prime lens these things should last much longer. But to answer your question, yes, in my experience these things will not be as sturdy as a true EF mount.

My Fotodiox adapter is loose too. I have a Haoda Pro adapter that fits snugly but can't reach infinity.
-Robert

Thanks for the responses. The play/lash that I described is actually created by the unperfect fit between the adapter and the Nikon/Nikkor lenses. As far as I can tell, the Camera/Canon side of the adapter is a perfect mate with the 7D. I didn't think this would be too big of a deal but it would be nice if the adapter fit perfectly to the lenses.