I assume the fill flash on the camera does TTL, but I don't actually know. Time to go back to the manual.
I guess I should have metered off the heron's head and that would have under exposed the bird... but that is recoverable in PS.
I actually did manual bracketing with the built in flash, with exposure comp. It did make for a better exposure, but I still blew the head out every time. I didn't think of FE lock. I should learn more about that. Thanks for the tip/reminder.
I've never had a camera with *any* type of flash before the 10D (my prev was the Pentax K1000. Bullet proof, but almost totally manual and only has a hot shoe.) So I'm still learning a lot about this.
Canon put out a pamphlet called "flash work" which is supposed to be very good and detailed about how eTTL works. I saw this post on another fourm from Chuck Westfall, Director/Technical Information Dept. Canon USA:
Canon USA offers the "Flash Work" brochure (publication number CT2-1705-002) for people who are interested in learning the basic concepts of E-TTL, FEL, FP Flash, FEC, FEB and other related Canon flash terminology. If you haven't read it yet, please order a free copy through our Customer Support Center at 1-800-828-4040.
but as of 6/3/2003, they are out. This link, with all its bad spellings and some bad translations, is the complete booklet:
I will moste certainly read it when I get a ETTL capable flash.
Thanks for all the ideas and suggestions.