If one were to make a custom adapter for the micro 4/3 camera for an odd lens, what is the critical "measurement"? I assume it's something like flange to "film registration" plane? Or something like that. It seems that the various legacy lens adapters for micro 4/3 vary in length (i.e., depth). I have a couple of old Argus lenses and think it might be a neat experiment to try and fabricate an adapter of some sort. Your thoughts?