see also:

• 3x telephoto zoom lenses for Micro Four Thirds
• 3-4x super-telephoto zoom lenses for Micro Four Thirds
• 8-10x super-zoom lenses for Micro Four Thirds
• wide aperture telephoto in 135-150mm range for Micro Four Thirds
• super telephoto lenses

• 300mm lenses on Micro Four Thirds system effectively gives a 600mm field of view in traditional 35mm full frame terms
• most of us do not need such super telephoto capability but it does come in handy for:
  • astrophotography - particularly moon shots
  • wildlife photography
  • sporting events although most venues will not allow lenses with greater than 200mm focal length (to protect the rights of professional photographers who have paid for this right)
  • highly compressed perspectives
• gaining 600mm field of view on a full frame system generally means a big heavy lens that must be used on a tripod
• on Micro Four Thirds you may be able to get away without a tripod, and certainly you can get by with MUCH less weight and size
• the following excludes consumer grade super tele zoom lenses for MFT - see 3-4x super-telephoto zoom lenses for Micro Four Thirds, and mirror lenses such as Kenko / Tokina 300mm f/6.3 macro mirror lens for MFT, and Samyang / Rokinon 300mm f/6.3 mirror lens

• Olympus mZD 300mm f/4 PRO lens
• this lens is the holy grail in 300mm lenses for Micro Four Thirds shooters
• it will be the only 300mm lens with:
  • weatherproof
  • wide aperture of f/4
  • CDAF optimised silent autofocus
  • almost zero aberrations and exception sharpness, although best at f/5.6
  • 6.5EV image stabiliser when used as Dual IS with compatible cameras
  • MF clutch
  • excellent close focus performance
  • relatively compact and light

• Olympus ZD 50-200mm f/2.8-3.5 lens
• AF will be stutteringly slow on most bodies, although the E-M1 will allow faster phase detect AF
• sharp lens wide open, although not quite as sharp when used with teleconverters
• when used with the 1.4x TC, you can get to 280mm f/4.9
• when used with the 2.0x TC, you can get 100-400mm f/5.6-7.0 and at 150mm it will be 30mm f/6.6
• the problems are:
  • slow AF
  • big, heavy lens (1.07kg), and almost absurdly long when extended even to 135mm focal length when the hood is in place (10.5cm longer than the Canon EF 135mm f/2.0L lens with its lens hood)
  • requires four-Thirds adapter
• advantages:
  • gives best telephoto range
  • close focus 1.2m
  • has tripod mount
  • nice bokeh for a zoom lens
  • can be bought at reasonable prices 2nd hand
  • can be used with Olympus ZD tele-extenders (EC-14 and EC20)
  • weatherproof

• Olympus ZD 150mm f/2.0 super telephoto lens
• gives 300mm f/4
• a beautiful lens BUT AF will be stutteringly slow on most bodies, although the E-M1 will allow faster phase detect AF
• very sharp lens wide open although not quite as sharp as the 300mm f/2.8
• the problems are:
  • slow AF
  • still expensive (>$A3000 new perhaps $A1700 2nd hand)
  • very heavy (1.6kg, 82mm filter)
  • close focus 1.4m
  • requires four-Thirds adapter
• advantages:
  • option of using it at 150mm f/2.0
  • has tripod mount
  • nice bokeh
  • not too big
  • can be used with Olympus ZD tele-extenders (EC-14 and EC20)
  • weatherproof

• Olympus ZD 90-250mm f/2.8 super telephoto lens
• a beautiful lens BUT AF will be stutteringly slow on most bodies, although the E-M1 will allow faster phase detect AF
• very sharp lens wide open
• the problems are:
  • slow CDAF
  • still v expensive (>$A5000 new perhaps $A3000 2nd hand)
  • very heavy (3.27kg, 105mm filter)
  • close focus 2.5m
  • requires four-Thirds adapter
• advantages:
  • has tripod mount
  • nice bokeh
  • can be used with Olympus ZD tele-extenders (EC-14 and EC20) to give:
    • 126-350mm f4 (with 1.4x TC)
    • 180-500mm f/5.6 (with 2x TC)
  • weatherproof

• Olympus ZD 300mm f/2.8 super telephoto lens
• a beautiful lens BUT AF will be stutteringly slow on most bodies, although the E-M1 will allow faster phase detect AF
• very sharp lens wide open
• the problems are:
  • slow CDAF
  • still v expensive (>$A6000 new perhaps $A3500 2nd hand)
  • very heavy (3.29kg, 43mm drop in filter)
  • close focus 2.4m
  • requires four-Thirds adapter
• advantages:
  • has tripod mount
  • nice bokeh
  • can be used with Olympus ZD tele-extenders (EC-14 and EC20) to give 600mm f/5.6 (with 2x TC)
  • weatherproof

• Canon EF 300mm f/4L IS USM lens
• a full frame lens
• very sharp lens wide open
• the problems are:
  • no AF on MFT, must use magnified MF or other MF assist
  • no aperture control
  • requires EF to micro-four-thirds adapter
• advantages:
  • nice bokeh
  • close focus 1.5m
  • not too big nor heavy (1.19kg, 77mm filter)
  • weatherproof
  • not too expensive
  • can be used with Canon EF tele-extenders
  • can be used with a Metabones Speed Booster adapter to give aperture control and reduce down to 213mm f/2.8
  • can obviously work as an AF lens on Canon EOS cameras

• Olympus OM 300mm f/4.5 manual focus lens
• when compact size trumps AF
• only 1000g and 181mm long, 72mm filter
• will need OM-MFT adapter
• built-in lens hood
• close focus 3.5m
• best stopped down to f/5.6 to reduce purple fringing