Canon EF 200-400mm f/4L IS 1.4x Super Telephoto lens made an appearance at NAB Show 2013. This lens first rumored to launch with EOS 7d Mark II DSLR camera then another updated rumor told the lens will be available in Mid 2014.
According to CR, the mid 2014 launch is untrue and the Canon EF 200-400mm f/4L IS 1.4x release date is May 14,2013. The official announcement of the lens is close and the availability to be in September/October 2013.
The weight of this lens is pretty close to the EF 600mm f/4L IS II. Canon EF 200-400mm f/4L IS 1.4x price expected to be over $10,000 as rumored before.