Can some explain to me in basic terms what HDR does and why I'd want to use it? Also how should I control the flash on the iphone while taking shots. I have had mixed results thus far taking photos. Allot of pics look great on the ipod screen but when you get them blown up onto a nice tv, they dont seem to stand up to shots taken on my 12mp digital camera. I am imagining because its only 5mp. So they look fuzzy when blown up. I want any tips for taking clearer, sharper, better more colorful pics with the iphone 4.