Thanks Mat and Leaf.
I've seen mixed comments on the 70-200 and 2x combo. Some say it's great and there's very little quality loss and others say the extender is useless. I'm leaning toward giving it a try. If it doesn't meet my needs I can always sell it.
I suppose a fair test would be the 100-400 no extender at 300mm vs the 70-200 with the 2X at 300mm equivalent. The 70-200 is a very sharp lens! Then I might add in that the extender is at least 25-30% the cost of the 100-400 lens! Maybe not such a bad deal? Extender works on a variety of lenses, which may make it useful. I have a 2X which I intend to use on the 400mm f/4.5 some day to make it an 800mm. Hope it works?
Tape mod for the extender so it works on slower lenses. Might as well add it, because I use this method and someone is bound to wonder which three pins need to get covered.
