As you may have noticed, the contax SlRs have a button to release the lens. The adapters,however have a small "feder" that you have to move with your fingernail. I have experienced that this type of securing mechanism can fail (but luckily the lens did not fall). So; not only the auflagemass must be exact, but the method of securing the lens must be reliable. Nochmals, entschuldige; kein Deutsch.
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