It's generally accepted that sharpening should be the very last thing you do to an image before you save it. Digital sharpening works best on areas of adjoining markedly different contrast. Any contrast, or other levels adjustments you make after sharpening can therefore have an adverse affect on the sharpening you've already done.
Even if you shoot jpegs, you're better off disabling all sharpening in the camera and dealing with the sharpening in processing, unless you're working against the clock like many media togs and need respectable images straight out of the camera.