Have you told Bob about your problems with the adapters you have? I know that he has sold hundreds of them, and personally know of many satisfied customers. Others (as well as Zeiss) claim that they fit perfectly and precisely. It's possible, however rare, that you got a bad one or two. Contact Bob and I'm sure he'll set it right. It's a fine product, execptionaly well made to Canon and Zeiss specs and tolerances, and he personally stands behind it.