Here are the results of my research on follow focus with the 20x auto lens.

I made a new post, "Canon 20x auto lens follow focus accuracy"
http://www.dvinfo.net/conf/showthread.php?s=&threadid=38166

Read your test findings Mark, good job.

Sounds to me like breathing or not, that 16x manual is looking more attractive now...?

Thanks Charles and you are right. After using both lenses I prefer the manual. The 20x has a longer reach, but I'm pretty much sticking with the 16x manual.

I'm a 14x manual guy myself. I like having the iris ring where it should be, and I rarely seem to need more on the long end.

Ya! What the heck was I thinkin', eh?