To clear up any potential confusion, this is NOT Sony Alpha, but Alpa of Switzerland. You will most likely be using the Kern Macro Switar 50mm f/1.8 or f/1.9 apochromat lens on this adapter.\n\nWhy Metabones®?\n\nSince its inception, Metabones has been designing and manufacturing lens adapters recognized among professionals and enthusiasts as leaders in design and workmanship.\n\nContrary to the popular trend of other factories using an aluminum ring painted black on the camera-body-side, we instead take no short-cut but use precision-machined brass with chromium plating on both the camera-body and the lens sides of our adapters, in order to ensure smooth mounting, great appearance, and durability. The lens side of the adapter features a strong leaf-spring structure, strengthening the adapter-lens connection and ensuring tightness of the lens in order to reduce wear and prevent focus errors and optical alignment issues from appearing.\n\nMetabones uses matte-black treatment to keep internal reflection to a minimum in order to maintain the maximum optical quality possible with the lens.\n\nAll Metabones Adapters follow this tradition of uncompromising precision, robust build quality and outstanding finish. Our new Smart AdapterTM series of products add industry-leading electronic interfacing technology from Canada, with true electronic control of the lens' aperture directly from the camera body.\n\nFeatures\n\n- Both camera-side and lens-side of the adapter are made of brass, precision-machined and plated with chromium.\n- Satin surface finish - just like your OEM lens and camera mounts.\n- Precise fit and solid connection - lens has no play, gap or wiggling when mounted on adapter and no adjustments are required to fit your lens.\n- Designed to reach infinity focus while maintaining the correct registration distance required to maintain optical quality of CRC lenses or lenses with floating elements.\n\nOur Smart AdapterTM series adapters have the following additional features\n\n- True electronic integration of aperture diaphragm - let camera automatically choose aperture in P or S exposure modes, or dial in yourself on the camera body in A or M modes.\n- EXIF data such as lens identification, focal length and aperture.