I'm still mildly confused because the e520 manual doesn't really say anything at all apart from imply that having all three points on is AUTO mode. I'm just intrigued to find out how auto mode actually decides what to focus on. It must be a similar issue for E3 owners because they've got 11 (I think) autofocus points. If you set the E3 to 'auto' what happens then? It must be an interesting algorithm if it seems to get it always right but it makes you wonder whether those occasional pics that are slightly out of focus might be down to not understanding how 'auto' autofocus is working. I think I'll set my camera to centre spot focus for the time being