Question about Omega D5500. I received a Rodagon 135mm and 50mm lens both attached to lens boards. I tried to unmount the 135mm and place an 80mm Nikon to print Medium format. The lens seems to be permanently attached. Now there is some play (looseness) of the lens/board combo. Can this lens be removed, if not, how do I retighten it? My durst M67 allows me to simply unscrew the enlarging lens. I guess I'll need a lens and board?