Within my expectation of the product - be aware that this adapter ring as no electronic contacts for aperture control of EF lenses without aperture control ring. Best is to attach the designated EF lens on an EF mount camera, select the needed aperture, then release the lens from the EF-based camera while the DoF button is pressed. This way the aperture remains set within the EF lens after it is detached from the camera. Next the lens can be mounted with set aperture on this adapter. My adapter ring showed a bit of resistance when rotating the lens into the lock position. Then the lens can be attached together with the adapter onto the M mount camera which worked smoothly. Focus has to be estimated manually with the meter scale of the lens since the camera does not know which kind of lens is attached, neither works the rangefinder patch to focus in camera.Tricky part is to demount the lens mount adapter from the M camera - the ring only leaves a small distance between camera lens release button and the adapter ring thread itself. You need either a thin finger or some pen to push down the release button.
06/12/2016