What could cause an Android activity to relaunch itself infinitely when returning from camera?
After much investigation, it appears the call to relaunch is coming from onConfigurationChanged. I still haven't figured out why, but at least I know what to avoid.
It explains why some cameras triggered this bug and others not: some cameras used the same configuration as my application, others not.
EDIT: I've discovered after other investigations that I had a bug in my extended Application class. In the onConfigurationChanged method, I was changing the configuration by forcing a certain locale. This was triggering a new onConfigurationChanged() call, which caused an infinite loop and the subsequent screen create/destroy sequence. I have no idea why I've put that code in the onConfigurationChanged() method, but I guess you have to suffer in order to learn :)