Most people have pretty low res isight cameras. If youre trying to read a really small QR code, its not going to happen. The resolution of the non-HD iSight cameras just isnt high enough to make out the details. I tried scanning a vCard QR code and the camera just cant make out the details at the size I have it printed. The 5MP camera on an iphone can make it out. But thats not the apps fault. The app is simple, free, and useful. It would be interesting to see if taking snapshots improves the performance.