Great, that helps. Thank you.
So if you go to the section in my camera recommendations article for Micro Four Thirds Lenses, I have walked through some things to expect when choosing a lens.
- To get a medium shot from 50' away, you will need a 200mm focal length
Now, with that information in mind, depth of field (amount of blur in background) is where things really get tricky...
If you don't want a lot of blur in your background, then you really need to keep your aperture/iris on the lens at f/8 or higher. And you may even want to set it closer to f/16 depending on how crisp/sharp you want everything to look.
This, in turn, also means that you need to have quite a lot of light (like, A LOT) to make sure that you're not having to turn up the ISO/gain in the camera to get enough exposure.
As you can see, these cameras, lenses, and camera settings all get rather tricky when you start working with longer distances and especially tighter shots at those distances.
If it helps you visualize this, you can use your current cameras and set them to 0 dB gain and an aperture/f-stop of f/8 or f/16 to get an idea of what you're dealing with.
Hope that helps!