I have a lens-reversal ring for a pentax k-mount camera (as far as i know, this will fit on any bayonet-mount pentax body, including the modern digital bodies). If you're not familiar with a lens-reversal ring, it is used to mount a lens reversely onto a camera body, which results in having a super-macro lens. In this case, it comes with an olympus om zeiko 50mm lens with it's bayonet mount removed. The reversal ring screws into the filter threads on the other side of the lens and turns any lens (with a 49mm filter thread) into a super macro lens. I'm interested in trades/money. shoot me an offer, i'm willing to negotiate.