Keep fussing with the settings on the Quickcam 4000. It gets good marks. You might also try flooding the image with what seems to be way too much light. Try a halogen hot shop light or two to fill in all the portrait you are attempting. Aim for even full illumination. You can get the ten dollar lights at walmart, or home depot.

No web cam will ever match the clarity of an upscale camera, but adding gobs of light sure helps bridge the gap.

Good Luck !