Canon 70-200mm f/2.8L IS II + Canon 1.4X EF Extender II
Just added to my review of the Canon 70-200mm f/2.8L IS II in DAP is a new page showing performance at 200mm with the Canon 1.4X EF Extender II (eg 280mm f/4).
Apertures f/4, f/5.6 and f/8 are shown with crops from 7 areas of the frame.