...ok, so there is a spec or two of dust inside my boyfriend's 70-300mm lense...he is wanting to know if he can safely take the lense apart and remove them, because he swears that the dust shows up in the sky of pictures he takes outside. I've told him and told him that the specs are dust on the sensor, but he says I'm wrong. Am I wrong? and can he safely open up his lense and clean it? Thanks in advance guys and gals!