Panasonic GH5 + 200mm f/2.8 vs. the Canon 1D X II + 400mm f/2.8 (Image by IR).
Imaging-resource posted the Panasonic 200mm f/2.8 review:
The Panasonic 200mm f/2.8 POWER OIS LEICA DG ELMARIT is a wonderful and long-awaited lens for those advanced and professional-level Micro Four Thirds shooters. Although older Four Thirds DSLRs enjoyed a handful of pro-level telephoto zooms back in the day, the newer Micro Four Thirds finally seems to be catching up with telephoto and supertelephoto offerings. As of now, the Panasonic 200mm f/2.8 is the longest and brightest supertelephoto lens available for MFT cameras. Offering a classic 400mm-eq. focal length and wide f/2.8 aperture, the lens is perfect for action, sports and wildlife, and especially so thanks to the bundled 1.4x teleconverter — an unexpected but very welcomed little addition from Panasonic! Furthermore, the 200mm f/2.8 maintains the classic downsizing — both in physical dimensions but also in price — that’s seen with other Micro Four Thirds lenses when compared to DSLR counterparts.
Optically, the lens is excellent, the AF performance is fantastic and the build quality is very rugged, as we should expect from a pro-level lens. Sports and wildlife fans who’ve downsized to Micro Four Thirds, here’s your premier f/2.8 supertele lens!