Some of you use M mount lenses on Sony cameras. Most of those have terrible close focus ability by today's dslr standards. Have you considered buying a close focus (helicod?) adapter. I recently acquired a voigtlander M mount lens and I'm looking at the options. The voigtlander version is out of my price range at $300 but I have found some shiny looking chinese versions for below 100. It is still a lot for an adapter but I'm worried about the function too. Does these work?