Are there Nikon BR-3 like adapters for other brands?

<p>If you don't know what one is, the BR-3 allows you to use a 52mm filter, on a reverse mounted lens. Which is great to protect the rear lens element. Or, if someone knows what the correct nomenclature would be.</p>

<p>Yuri</p>

<p>I have never seen anything. I looked through a couple of books and catalogs, including one that purports to show all the Minolta lens accessories from back in the x-700 era. Not a trace of a BR-3 equivalent. It looks as if Nikon scooped everyone on this.</p>