If you're a photographer looking to maximize the potential of your Slr or Dslr camera, the FotodioX Mount Adapter is an essential tool. This adapter allows you to use your existing Contax 645 lenses on any Sony Alpha Dslr camera body, eliminating the need for additional lens purchases. The FotodioX Mount Adapter is part of a comprehensive range of adapters, catering to various formats from large to small. By adapting larger format lenses to smaller format sensors, such as large format to medium format, medium format to 35mm, or 35mm to micro 4/3, you can achieve exceptional edge-to-edge sharpness. This is due to the smaller image field, which helps minimize lens distortion and aberration by utilizing the 'sweet spot' or center of the larger lens image circle.Constructed with high-standard precision, the FotodioX Mount Adapter features a leaf spring design that holds the lens securely to the camera body, eliminating any play between the two.