[kammychu]

7D+20-200mm 2.8 IS II+Canon EF Extender 1.4X III後
除了光圈會低一級外還有什麼不同呢！
希望同門師兄幫幫小弟解答！
謝謝！

[kammychu]

更正
70-200mm

[EagleChui]

Picture quality is still very good, focusing a little bit slower. Good combination to suggest to new comers.

[hotfire009]

I have owned both 2x II & 2x III before and tested both TCs for a long time to justify the difference. MK III only keeps the frame edge a little bit better than MK II. It is surprised that the centre of MK III is a little bit worst than MK II. ISO is even a little higher than MK II at the same EV. No different on AF is observed. In conclusion, just a little bit difference which is hardly noticeable. So I suggest not to waste money on MK III as MK II is good enough.

[Billyeung]

lots of reviews echoed hotfire009's views.
Agreed