You do a fine job of keeping your spine in extension. However, watch the bar when you start the pull. It drifts away from you a little and you move it around your knees. You can rectify this by starting with a more horizontal back angle. Look for Rip's deadlift setup "perfect every time." I think that's what it is. Google will help. It works nicely for getting into a good position for the deadlift. You will be tilted over more, your knees will be more extended and you will be able to drag the bar up the shins in a more or less vertical plane.