HD, Try setting your camera to macro mode before taking close-ups.
Do you use chalk? Using it will help reduce the amount of callusing that builds up. Also, when you grip the bar try not to hold it too high in your palm so that once you lift you pinch the skin of your palm. That will exacerbate the problem. Instead, set the bar so that it rests in the crease between your palm and fingers. If you have it right, it shouldn't slip any lower when you lift.