One shot would be impossible. It uses 3 main pictures, one straight on picture, one picture of the back, and one picture of the front of the card on an angle. Using these 3 its able to identify the exact centering, edge wear, and surface scratches that are going to affect grading and give you a fairly accurate grade. I've used it on a few PSA submissions myself and so far I am very happy with its correlation to the grades on the cards i got back.