Canon EF 300mm f/2.8 L IS II USM Lens with 2x III Extender Full Size Sample

As I mentioned recently, I used the Canon EF 300mm f/2.8 L IS II USM Lens with the Canon EF 2x III Extender as a lightweight, handheld bird photography lens in Florida in early March and found the results to be quite impressive.
 
The Canon EF 800mm f/5.6 L IS USM Lens served as my primary tripod-mounted birding lens for this trip (the perfect full frame choice), but the 300 L II, along with a 1.4x III and a 2x III filled the handheld and wider focal lengths needs. And did so remarkably well.
 
My initial comment stirred many inquiries about the 300 II + 2x III combination. I'm not a big extender user, but the Canon EF 300mm f/2.8 L IS II USM Lens is so amazingly sharp that the with-extender results are still remarkable. And I had no problems handholding the with-2x-resulting 600mm f/5.6 L IS USM Lens.
 
I have uploaded a sample picture from this combination for your review. The Brown Pelican image was captured near sunset at f/8 (f/5.6 results are not as sharp), 1/250 with a handheld Canon EOS 1Ds Mark III in RAW format using the Neutral Picture Style (lower contrast for better histogram). The JPG sample was processed in DPP using the Standard Picture Style, sharpness set to "2" (low) and saturation set to "1".
 
Here is the sample: JPG (11.0 MB) | RAW (26.4 MB)
 
License granted for personal gear-evaluation purposes only.
 
I will add this full size sample picture to the Canon EF 300mm f/2.8 L IS II USM Lens Review for more-permanent reference.
 
B&H has the still-elusive Canon EF 300mm f/2.8 L IS II USM Lens (and Canon EF 400mm f/2.8 L IS II USM Lens) in stock at this moment.