Review on Concept Adapter Mirrorless Cameras Matting by Duane Ramos

My K&F Concept MD-NEX coupling broke after only three days of use. Lenses attached to it no longer snap into place. The bayonet mount still holds the lenses, but after focusing or changing the aperture I have to be careful to tighten them back up. It still works but broke after three days? To put it mildly, a little disappointed. It's too big a problem to send it back; I will use it until it fails completely, then I will buy another one. A million years ago (well, more like 35 or 40) I had a cheap 2X teleconverter that wore out the same way, but that was after several years of use. That aside it still works like a charm and would have been a 5 star if my example wasn't so fragile. Rokkors is too great an opportunity to pass up. Update 5 February 2021: The camera bayonet flange for this thing is now loose and unusable. With difficulty or not, he returns to Revane. Will probably consider another manufacturer. Shame. It looked great on my camera, but in less than a week of use it wore out completely.