[ I did not find a pertinent thread via forum search; if this is a duplicate question, please be so kind to provide a link, otherwise feel free to answer  ] 
  
What adapters can be reliably used on the M10 for e.g. a classic LTM Elmar 50 mm in your experience? 
In older threads (pre M10), the three most widely recommended were 
- Original Leitz (50mm seems to be a bit scarce on the market) 
- Voigtländer 
- CameraQuest/ Rayqual (seem unavailable in Europe) 
  
The M10 has been reported to be more finicky with regard to 6 bit coding. Is it also more of a diva with regard to adapters? 
  
I have read the caveats about collapsing; now I am looking out for an adapter... 
  
Thanks, 
Mathias