Larsskv said:
I just checked on my brand new 85L f1.4, which I am on my way out to test. ;D
The hood that comes with the 100-400 L II does not fit very well at all. For some reason it is hard to turn around, and I would be afraid to break it if I were to use it.
The hood that comes with the 70-200L f 2.8 (non IS) - ET-83II - fits very well, does not cause visible vignetting, and must be deep enough to keep raindrops out. I guess it is a little less deep than the ET-83C, but it should be sufficient.
Just to follow up, I can confirm that the EW-83F fits on both normally and reversed absolutely fine (better in my case than the ET-83B II which feels stiffer somehow) and, having tested it further, does not vignette at all. It is also somewhat longer than the ET-83B II, even at the shorter petal, so may provide even more rain cover.
It also still seems to be a stock item, at least at WEX in the UK where I have just ordered one (currently on half-price discount).
Cheers