Rayqual Contax Film SLR to Canon EF Adaptor

The Rayqual adaptor ring is a superior product that is finely engineered and beautifully finished. It is made to a finer tolerance than many of the other adaptor rings currently available and is supplied complete with a fit rear cap, so that the adaptor may be left on the lens when not in use.
The Contax to Canon EF adaptor ring in paricular has been noted as "having minimal amount of loose play between lens and camera body (too little to notice) compared to the usual rings available, and they are easily dismounted if necessary with an easy to use lock mechanism"

Although it has no electrical connections, and therefore limits the abilities of the EOS camera that it is fitted to (Manual mode only and no metering, other than via the post view histogram), there is a large body of interest in fitting non EF lenses, as there are particular lenses that work very well with the full frame EOS 1Ds range in particular.