see also:

• a catalogue of Micro Four Thirds lenses
• 25mm "standard" lenses for Micro Four Thirds
• 17mm "wide angle" street photography lenses for Micro Four Thirds
• https://mirrorlesscomparison.com/micro-four-thirds-lenses/olympus-45mm-vs-panasonic-42-5mm-vs-nocticron-42-5mm-vs-voigtlander-42-5mm/

• There are a number of 40-50mm lenses for Micro Four Thirds system which give the full frame “80-100mm portrait lens” field of view, and for reasonably shallow depth of field (DOF), the lens should have a widest aperture in the range f/1.2-f/2.0 (you can go to f/0.95 but these lenses tend to be less sharp and only manual focus)
• Note that most head and shoulder portraits on full frame cameras are shot at 85mm f/2.4-2.8 to ensure ears to tip of nose are in acceptable focus which equates to f/1.2-1.4 on a Micro Four Thirds lens in the 40-50mm range
  • some people like the extreme shallow DOF images where ONLY the eyes are in focus, for this you will need a full frame camera and a 85mm f/1.2 lens which is very expensive and quite difficult to focus accurately at f/1.2
• If you are budget minded or want a compact, light solution then there are two very serviceable options:
  • Olympus m.ZD 45mm f/1.8 portrait lens
  • Panasonic G 42.5mm f/1.7 Power OIS
• If you like macrophotography and want a dual purpose lens, then consider:
  • Olympus ZD 50mm f/2.0 macro lens with a Olympus Four Thirds dSLR system adapter HOWEVER AF will be slow!
• If you want to get an even more shallow depth of field (DOF) with AF and are prepared to pay a LOT more, then there are these options:
  • Panasonic Leica DG 42.5mm f/1.2 Nocticron lens
  • Olympus mZD 45mm f/1.2 PRO lens - coming late 2017?
• If you want the shallower depth of field (DOF) but can't afford the above, then consider manual focus lenses