Here's my dilemma. I'm going to get one of two lenses. I was looking at the 100-400mm , but I'd really love to have a faster lens. So that got me interested in the 70-200 2.8.


So, I was have been researching, I find that the 2x lens extender would give me the same final focal length, and same f stop as the 100-400mm on it's own, but I'd be able to have a really fast lens as well.


I'm going to get the lens in the next month or so (I hope) so I was wondering if anyone could help me understand how much an extender really degrades the quality. I've seen the shots on this site with them, and the pictures still look phenominal. If at 400mm, the image quality won't be much different between the 200mm with 2x, or just the 400mm alone, I think I'd want to get the extender, because I really would love the faster lens.



Can anyone help? Thanks a lot.





John