I will be getting the Canon 70-200mm f/2.8L IS lens and will use it on a full frame camera (5D).

I wish to get somewhere near 400mm from this lens to take the occasional Bird shot (a dedicated lens is out of the question right now), and am tossing between the 1.4x and 2x teleconverters from Canon.

Which would be the better option:

1) 2x teleconverter giving 400mm zoom but less image quality

2) 1.4x teleconverter giving 280mm zoom with slightly better image quality and crop the image to have a field of view similar to 400mm ?


Regards,

Finn