| Canon Extender EF 2x II Specifications | |
| Focal Length Magnification | 2.0x |
| Lens Construction (groups) | 5 |
| Lens Construction (elements) | 7 |
| Maximum Diameter x Length | 71.8mm x 57.9mm (2.8" x 2.3") |
| Weight | 265g (9.3oz) |
Reviews
Source
SLRGear.com
We reviewed the Canon 400mm ƒ/5.6L USM back in 2008, which makes a good candidate for comparison with the 200mm ƒ/2.8L USM and 2x Extender attached. In terms of sharpness, the two are quite similar: the 400mm is slightly better at ƒ/5.6 and ƒ/16, but at ƒ/8 and ƒ/11, they're almost identical.
The-Digital-Picture.com
My advice is to use the Canon EF 2x II Extender to extend the usefulness of a very sharp lens that has another more primary purpose. Said another way, you generally will get better results from a 400mm lens than with a 200mm lens + the Canon EF 2x II Extender.
Luminous-Landscape.com
If you have a Canon system and think you need, or at least want a 2X Extender, then the new model is about as good as it gets. If, as I do, you already own the previous generation then I wouldn't be in a rush to replace it.
