I have a good collection of MD lenses so I was prepared to buy the adapter and make a trial to see whether they could be used on my M4. The adapter seems well made and allows me to connect an MD lens to my M4. However the rangefinder has not coupled (in line with my expectations) so I will set distances manually. I have yet to run a film through the camera using this set-up so I can't say yet how well it functions and give you a final verdict. It rather depends on your definition of 'work'