well the iphone 4 is very good for pictures and videos, maybe you would want to select HDR on, it takes more then one pic when you press the button to take pics and you can see the better quality one
Welcome to the forum. If you don't mind spending some money in the app store you can look up for a better camera app in the app store. Good ones that i use are camera pro+, and genius camera. Both are great for photos and videos.