you can tweak and tweak all week till you cant speak and your n900 photos will stil be weak!!!!
this camera is trash and nokia wont lift a finger to change it cause it would be too expensive to come up with some kinda hardware change for every one who brought one

here is ma advice. if yours is still under warrenty which they all should be' just send it back for a brand spanking new model. hopefully the newer models have this problem fixed