hey i have that problem too! it's liike that lar.. unless u get
pro lenses which are expensive.. even then.. the quality at ANY
lens' extreme is always worse than at it's sweet spot. (which is
not at it's extremes - focal length or aperture size).
but i still have to nag leh... poor quality of lenses shouldn't
deter u from taking THE shot. the lens i took these shots with are
HIDEOUSLY soft at 300mm... but i still take, and i still love these
photos, it's the moment i captured, who cares wat equipment, or how
good they are, i used? 
