Is the EF 200-400mm f/4 L IS USM Extender 1.4x Lens the new Black?

[eldarhau]

I currently use the 70-200 f2.8L IS II and 400 f2.8L IS II lenses, with or without the 1.4xIII and 2xIII extenders, on 5DIII and 1DX bodies. It requires 2 body/lens combos and more parts, but I can´t say I´ve been bothered with that. If I got the 200-400 1.4TC I would probably still carry the 70-200. The IQ on the lens/body combos I have is so good that I can crop significantly and still maintain excellent results, so I am not sure I would feel closing the zoom gap would feel like that much of an improvement. If I were to add anything to my current long lens alternatives, it would most likely be the 600mm f4.0L IS II, since the 5DIII and 1DX bodies support AF at f8.0.

The Nikon alternative cost 5k$ less, which makes the 1.4x extender a very expensive one. Looking at Bryan´s test charts for the Nikon, I believe the Canon lens will show better performance, but still.

The areas I think I would be happy to have the new lens is in bad weather, high dust environments etc., where I don´t like to change lenses and on safaris, where I would normally carry just one body and the maximum zoom range would come in handy. The rest of my shooting would most likely be either 200-400 or 280-560. Flipping between them would probably not be of significant importance to me. But I know for sure that I would miss the f2.8 apertures and the use of my bodies full AF performance.

I know myself well enough to know that I cave in sooner or later for the temptation, but I can´t see that it will add anything or replace the lenses I currently use to be worth the price.

/Eldar