Fotodiox Excell+1 from Fotodiox Pro, Contax / Yashica Lens to Micro 4/3 (MFT) DSLR Lens Mount Adapter with Focal Reducing Light Gathering Optics Fotodiox Pro Premium Grade "No Play" Adapter Top Notch Craftsmanship, Infinity Focus Guaranteed Modifies existing camera crop factor by 0.72x Light gathering optics gain 1-stop of speed 24-Month Manufacturer Warranty