Recently i bought a Canon 70-200mm F4 L. I want some more reach on my lens and want to buy a 1.4x teleconverter. By adding a 1.4X i will loose 1 stop of light and AF will slow down. Can somebody tell me if the Canon 70-200mm will AF better with the Canon 1.4X TC or the Sigma 1.4X TC. I came across some reviews, which say that the Canon 1.4X TC is designed to slow down the AF to get an accurate focus. But Sigma 1.4X TC is not designed that way and it may overshoot a bit in either direction. Is it true?? Also if there will be any major differences in the image quality between the TCs?? I would love see some sample images with the Canon 70-200mm F4 + Sigma 1.4X TC.
Thanks in advance.
