It's actually difficult to manually focus on the E510, because of the lack of focussing aid and the size of the viewfinder. Also, the kit lenses have no focussing scale on them (common to most brands) But the focus control is not physically coupled, so there is no place you "can't turn it any more". That means you can happily spin it till the focus stops moving.
As a matter of course, I tend to leave the focus to S-AF+M - that allows you to trim the AF if you think it has it wrong.