I've been looking around for a teleconverter and found many confusing opinions and 'facts'. I have a 400D and want to use the TC with a 70-200mm f/2.8L IS USM. I looked through this page http://www.traumflieger.de/objektivtest/telekonverter/telekonverter_check.php But my German is not good enough to understand all, I can see the images though and it seems like the Kenko Teleplus SHQ 1,5x produces the sharpest images. So what else is the difference between these TC's; - Kenko Teleplus SHQ 1,5x (107) - Kenko AF 1.4 Teleplus Pro 300 DG Teleconverter (189) - Canon Extender EF 1.4x II (289) My main concerns are if they will autofocus with previously mentioned lens and what my maximum aperture will be. And ofcourse if anyone has experience with one of them, please let me know what you think of them. THNX in advance!