Head and shoulders above its predecessor !!

I have to think longer determined these to order Canon Extender EF 2x III and have to say after a long Testfase:
It's really a dream what the developers of Canon have done here and around miles better than its predecessor EF 2x II.

Use the article alternately with my EOS 5D Mark II and EOS-1D Mark IV each with the new EF 70-200L f / 2.8 IS II.
Without exaggeration, a real dream combination of two cameras.
Forgot my 100-400L now sold - I no longer since I use the converter need.
A pleasant side effect: 1.5kg less in the backpack and some 700 euros more in the wallet.

For converter itself:
Top-quality workmanship and design to match the white L-series.
The converter takes, as its name (2x) already says a doubling of the focal length of the lens jeweilen.
In my Cams that the 5D (full frame) in 1D (1.3 crop factor) are 400mm with a 200mm lens and umgerechtnet 520mm on KB.
As led by Canon in the description it cost to use the converter loss 2 aperture steps (instead of 2.8 there are then 5,6)
I find further not tragic because my two cams from home bring with them from a very low noise Behave and I always PS (currently CS5) edit my pictures.
Autofocus work correctly and precisely, as I was accustomed to without converter.
The speed is slightly slower, is not really to carry out in flight captures fast raptors or lightning-fast cheetahs.
Image Stabilizer works despite Extenderverwendung very good and helpful.
The image quality remains at all focal lengths (70-200mm) equally well - can only minimal degradation at a magnification of the original notice from 400% - but that's in my eyes already nitpicking. See also my selected test images (4 pcs - 2x with and without Extender 2x).
The weight of the converter falls with my combination is not too much to the overall length (camera + lens + Converter + sunshade) of just under 42cm in my eyes is perhaps greater drawback.
You will notice WITH or WITHOUT Extender with SLR and a zoom lens in this size.

For me the best part where longer focal lengths are required for optimal image results.
Recommended and 5 stars.