Upload & Sell: Off
I use this lens nearly daily in my business (wildlife photography), especially with the 1.4x extender. Image quality is superb with this combination, even wide open, and focus is still plenty fast for BIF. I would warn that, in my experience, when using the 2x extender, I really need to shoot at near f/8 to get the tack sharp images I need to compete with those shooting the 500mm or 600mm lenses. This is the only drawback to the combo. The pluses include the fact that it is very hand-holdable, and much less of a burden to carry in the field.