The Novoflex Lens Mount Adapter allows a Leica R type lens to be mounted onto a Leica M type camera. Although the lens will fit physically, automatic diaphragm (AE metering) or any other functions are not retained using this adapter. In this case you will have to meter in "stop-down mode", since the lens does not have the ability to have its aperture controlled by the camera body. The current version of this adapter comes with a special 6-bit marking on the camera side to bring up the Leica R-lenses menu in your Leica M 240 digital camera.