ChadS
Thanks, I suspected that what you indicate was the case... just wanted to make sure. Appreciate your offer but think I will keep the 70/200 IS f/2.8 for the time being... Don't really know why but it seems to make sense (uh-oh).

The "hunting" is not all that common, just enough reports to get your attention... With good light/contrast the AF seems to work fine with the Kenko unit.

The 100/400 is the one lens that I would like to find a home for... The major on-line stores are only offering about half in trade of what they are selling the used units for... I would hit a happy medium... Doesn't really take good pictures sitting on the shelf at home!

Thanks for the input
Bill