The Extender EF 2x III features nine optical elements in five groups, ensuring improved optical performance. All optical elements have Canon's Super Spectra coating to reduce ghosting and flare. A new Fluorine Coating on the front and rear elements makes marks, such as spots left by water or fingerprints, much easier to clean than standard
6D + EF 100-400mmL II + EF 2x III Extender (Live View used for focus) - A different pic. 6D + EF 100-400mmL II + EF 2x III Extender (Live View used for focus) 6D + EF 100-400L II + ED 2x III Extender (Live View used for focus). Your needs might really dictate a need for f/2.8 for your photography. Especially if you like low light photography.
Canon EF Extender 1.4x II. Palm, 19 December 2014. Canon 5D Mark III, Canon EF 300mm f/4 L with Canon EF Extender 1.4x II at f/5.6 (wide open) at 1/640 hand-held at ISO 100, no lens profile used, Athentech Perfectly Clear v2.) Full resolution. It works well with the Canon EF Extender 1.4x II, making it a 420mm f/5.6.(2) the Canon 70-200 2.8 II + Canon Extender EF 2X III Obviously, buying the extender would be a lot cheaper and lighter than carrying around another heavy zoom. The Tamron would give me a little more reach, albeit the reviews say it's quite soft above 500mm.