see also:

• a brief catalogue of Micro Four Thirds lenses
• Panasonic Leica DG Elmarit 200mm F2.8 Power OIS lens
• Panasonic Leica DG 100-400mm ASPH f/4-6.3 lens
• Olympus mZD 40-150mm f/2.8 pro lens

• the Panasonic Leica DG Vario-Elmarit 50-200mm f/2.8-f/4.0 (100-400mm lens in full frame FOV terms)
• shipping May 2018
• compared with the Olympus mZD 40-150mm f/2.8 pro lens:
  • significantly lighter at 655g compared with 760g (The Olympus lens also needs the additional weight of the 1.4x TC to get to 66-210mm f/4)
  • significantly shorter at 132mm compared with 160mm for the Olympus (and a touch longer when you add the 1.4x TC)
  • has optical image stabiliser (and when used on the latest Panasonic cameras 6.5EV Dual IS)
  • compatible with Panasonic's DFD AF system whereas the Olympus is not - ie. if you have a Panasnoic camera - buy the Panasonic lens instead of the Olympus lens - for Olympus camera users either will be fine.
  • the additional native 200mm focal reach of the Panasonic lens avoids the need to use a TC and thus allows wider apertures than f/4 as you zoom out (although realistically this is only of significant benefit below 100mm and it is unlikely you will be shooting at this for most sports)
  • the Panasonic is probably a better choice for the kids soccer games
  • BUT the compromises with the Panasonic lens are:
    • lens gets longer physically on zooming - this could risk water and dust entering as you zoom out despite the weathersealing
    • no MF clutch
    • no Lens Fn button
    • the Olympus has a slightly closer focus at 0.7m compared to 0.75m for the Panasonic
    • the Olympus lens provides f/2.8 all the way to 150mm which gives shallower depth of field (DOF) at 150mm and allows 1 stop lower ISO for sports at 150mm

• 50-200mm (100-400mm lens in full frame FOV terms)
• widest aperture quickly drops from f/2.8 at 50mm to f/3.6 at 100mm, f/3.9 at 150mm
• weathersealed
• Power OIS image stabiliser
• close focus 0.75m
• 21 elements in 15 groups
• 9 rounded blades
• 67mm filter thread
• 76 x 132mm (2.99 x 5.20″) but extends on zooming
• 655g (1.44lb)
• $US1699
• compatible with DMW-TC14 and DMW-TC20 teleconverters
• no focus limiter switch
• large bayonet mount lens hood

• my blog post comparing it to Olympus and Canon alternatives
• The Hybris Shooter Youtube review
  • sharpest at f/4 between 50-100mm, and at f/5.6 at 100-200mm