I wanted to try out the use of spacer rings and thought I can not do so much broken with the low price. But therein lies the point, the price corresponds to the processing. The adapter segment that is set to the lens mount is coated. This coating bursts when screwing downright thereof, so that it can dirty the inside of the camera - the sensor, for example !!! I have returned the rings immediately.
These spacer rings to make more broken his camera, as that it enjoys.