Hello Fellow Medium Format Photographers: You may find the following story amusing if not educational: Last year I purchased a brand new Mamiya RB 210 APO lens (which sold for $3,800 at B&H in early the 2000’s) for $600 from a Far East Asia source on EBay. Optically, the Mamiya RB 210 APO lens was spectacular: I tested the lens on tripod, mirror up on Agfa APX 100 developed in Microdol-X 1+3 at 68F. The negatives revealed a lens that could resolve fine detail as well as my 35mm Nikon 105 VR Macro lens! There was a hint of early fungal growth – which I attribute to a humid storage in Asia – that was only visible upon close inspection. So I sent the lens into Mamiya America Corp in my home state of New York for service. My instructions were clear not to open the lens unless they felt assured that it’s optical performance would remain the same after reassembly. Peculiarly, they said many things upon receiving the lens: “Mamiya America Corp Service Dept. doesn’t clean fungus from lenses”, “the lens looks very clean to them”, “the lens had some internal dust” “Would I like them to clean the internal dust” (no). How could they not have seen the fungus? I wondered. Something seemed fishy. I received the lens back from them, and the fungus was indeed gone. (yes it was organic, fungus – don’t bother going there) There was evidence that the lens had been opened including internal dust that was not there before, and tool marks on a set of internal retaining rings that are not present on any of my other 20 odd brand new RB + RZ lenses. Fine, MAC told me a little white lie, but the fungus was gone, and they didn’t charge me. Great. When I finally had the chance to use the 210 APO lens again, Immediately noticed a lack of spectacular sharpness performance that was there before. So I did a thorough test of the 210 APO against a raft of my other brand new Mamiya RB telephoto lenses including the 180 KL, 250 KL, and 250 APO. The 210 APO was clearly optically inferior to all three – getting blown out the door by even the 180 KL!My Mamiya RB 210 APO lens in very clean now of fungus now, but extremely mediocre optically, and I am not happy. So last week I sent the lens back to MAC group with a gang of evidence including before and after transparencies and negatives and a complete recap of the above. I suggested that with the best of intentions either MAC group opened the lens and cleaned it, or sent me a different lens entirely and swapped the removable serial number sticker? MAC called me and at first said they will look into making things right, including possibly selling me a replacement 210 APO at discount. Then they called and said they don’t have any more 210 APO lenses, and are going to ship mine back and close the case. I received my original 210 APO lens back from MAC group today. It's the same jacked up lens they returned to me after opening it up. All’s well that ends well, but I am still waiting for my happy ending.