<p>Adapter ring? If you mean for a filter, I don't recall that this lens could handle one.<br>
If you mean for the body mount: No adapter ring needed, for this lens, if you get the one that Rokinon makes for the Nikon 1 mount.<br>
If you didn't buy that one, you'll have to tell us what mount you bought..... and then buy an adapter ring for that mount. However, I'm going to say, if you really got a different mount version of this precise Rokinon, return it!<br>
Rokinon makes some nice lenses. I had their MFT mount fisheye and LOVED it. I really miss it.<br>
But this one, in this topic, really misses the mark, imo.</p>