A couple of interesting patent applications have surfaced for new Nikon 600mm f/4 and 400mm f/2.8 lenses. The current versions of these lenses (the Nikkor 400mm f/2.8G and the 600mm f/4G) will be 7 years old in 2014.

Nikon 600mm f/4 Lens Patent

Nikon 400mm f/2.8 Lens Patent
Notably, these lenses were mentioned in the same patent application as the 800mm f/5.6 lens that was announced in June 2013. So, maybe we’ll see an update to the 600mm and 400mm Nikkor lenses in 2014…
[via Nikon Rumors]