Canon 300mm f2.8L IS II plus stacked TCs - looking for input
I am currently shooting a Canon 5D Mark III camera and Canon 400mm f5.6L as my 'bird lens'. Since the firmware update, I have used this combo on occasion with the Canon EF 1.4X III teleconverter as well.
I am interested in the potential of the Canon 300mm f2.8L IS II lens with stacked EF 1.4X III and EF 2.0X III teleconverters together. In theory this is a 840mm f8 combination, which meets the 5D Mark III autofocus capabilities. However, I realize that theory and reality may be different so I am curious to hear from anyone who has tried to use both of the newer Canon TCs in stacked mode with the 300mm f2.8L II lens.
I have seen multiple reports lauding the image quality and autofocus response with this lens and either of the version III TCs on it. I'm hoping someone has tested out the stacked mode using both of the version III TCs with this lens and can report their findings.
Thanks in advance,
Barry