I played around with an MD in the early 70's. My wife was working for a company that imported the Leisegang Colposcope, and they also carried Leica Md cameras to use on them so I could have got one "wholesale". It was cheaper than an M4 body and I wanted something to use with my Visoflex II-S as well as with my 19mm Canon lens. I ended up buying an M2 body with a blacked out prism for next to nothing instead. The MD series have no rangefinders, but they also have no viewfinder of any kind. The MD series are essentially the M4, M4-2, and M4-P bodies sans the range/viewfinder. At least the M1 had a viewfinder.
The Visoflex setup is great for extreme close-ups and long telephotos. I prefer the view through the finder to an SLR. I like the "chimny" finder for macro work, the prism with my 400mm. The chimny finder has a focusing eyepiece and it has the brightest most contrasty image you can imagine.
The Hologon was an amazing breakthrough when it was introduced in the early 1970's but it really needs the expensive center filter if you want even coverage. With the filter it's an effective f/16. Sell it to a collector and buy a 15mm Voigtlander Heliar. It's quite useable even at f/4.5, has a focusing mount and variable diaphragm, and costs less than a Mercedes SUV.
