Originally Posted by kristoffon 
no they don`t, just look at the two flower pictures just posted
I'm no expert on this, but my impression is that, when comparing lenses of different focal lengths at the same magnification, the area in acceptable focus isn't much different, but the *appearance* of the OOF areas is. The longer focal lengths will be more blurry in the OOF areas, but the size of the in-focus is comparable. At least, that's how things seem to me in my limited experience here.