Who is using this and what are your experiences with it?
I am especially looking for feedback regarding the eos 7dmk2 and canon 100-400 mk1 combination with this extender. Is it worth the price?
I'm using this extender with the 7dmk2 and a 300mm F2.8 IS mk1. It's a lovely combo these two, but I don't really notice any differences with the 1.4x II to be honest. So, when looking at the money side, I would choose the 1.4x II if I were you, it costs less and I don't think you will see a difference. In my opinion, having an extender on the 100-400mm at all, is not a good idea. You need a very bright day to be able to use it properly I think.
Many thanks on your feedback. The reason I would prefer the version 3 over the version 2 would be the (supposedly) better af performance at f/8.
I normal operational circumstances I am doing fine with the 100-400 as such, but especially with airshows I would love to have the extra reach for the high rolls, banks etc. Betting on the fact that most airshows are in the nice weather season and combined with my yearly bonus that I received yesterday, I took the gamble and ordered one.