There may soon be a new member of the Canon Extender EF lens family. A recently published patent filed by Canon describes a new 2.8x teleconverter. A 400 f/2.8L IS II would become a 1120mm f/8 lens with the teleconverter attached, though Canon will have to restore f/8 autofocus to its top-of-the-line cameras before that combo would become useful.
(via Egami via Canon Rumors)
