B&H & Adorama Have the New Teleconverters in Stock

[Hulk]

I wonder whether it is possible to stack a 1,4 extender on a 2x extender to get a x2,8 total extension. I don't find any information about this.

[Razor2012]

I tested both of them out at the local shop and was impressed.  At first I thought I'd never get the 2x, but after seeing it and reading what others had to say, I probably choose it over the 1.4.   I'll be using it with the 70-200 2.8II though. 

[drjlo]

I tested both of them out at the local shop and was impressed.  At first I thought I'd never get the 2x, but after seeing it and reading what others had to say, I probably choose it over the 1.4.   I'll be using it with the 70-200 2.8II though. 

Just ordered the Canon 2X III myself for use with 70-200 MkII.  This article re-emphasized how Canon did a really nice job with 2x III vs. 1.4x III.  IQ of 2x III stopped down looks VERY impressive!

http://www.deepgreenphotography.com/2011/01/the-new-canon-teleconverters-image-quality-comparison/