Thank you for your two replies, John. Not only I don't know the answers, I'm not even aware of all of the relevant questions :crazy:. You have been most helpful.

Note that I have already started a thread on a Canon XSi system in the Canon lenses forum, and don't wish to overlap. I will, however, make a study of the Olympus line.

Thank you, Greg and John, re the Olympus E520. It looks good at Steves and at some other reviews I found. I gave it a fair sell to the eventual buyer, but was unsuccessful. Familiarity with the Canon Rebel line was overpowering; the Canon XSi has now been decided.

I will now move to the the Canon lenses forum. Many thanks to all who have assisted with the choice of camera, and the related information (and the nice doggie pictures).