A rumor concerning the replacement of the replacement of the Canon EF 800mm f/5.6L IS USM (price & specs) lens.
The Canon EF 800mm f/5.6L IS II could be announced shortly after the Canon EF 200-400 f/4L IS 1.4x has (eventually) started shipping. According to the latest rumors this could due in Fall 2013. However, if there will be an announcement it will be a development announcement. Regarding used materials the new EF 800mm f/5.6L IS II will have a new build type, the optical formula is said to be “nearly identical” but improvements in vignetting and sharpness are possible.
Finally, some sources say the EF 800mm f/5.6L IS II could have a built-in teleconverter.
This will not be a cheap lens: the actual Canon EF 800mm f/5.6L IS USM has a price tag of $13,249.