I ended up mounting the wierd glass inside the tlr onto a spare lens board that i have. It turns out to be super wide-angle and does not cover 4x5. I plan to use it when i get a shutter for it. I also took apart a magnifying glass, and tried mounting that. looks really cool too. I'm going to buy some $10 wooden lens boards off ebay and start messing around with different lenses. should be fun. How do I figure out what f-stop to meter with? that's the only thing that's holding me back at this point.