Camera Quality: Outdoors, Day Lighting
The iPhone 4S features a higher-resolution camera (8 MP to the iPhone 4's 5 MP), but image quality is also enhanced due to the addition of an IR filter and additional image processing logic built into the A5.
Pictures taken with the iPhone 4 often look better than what the 4S delivers, mostly because the older phone takes pictures at a cooler temperature, for which we have a natural bias.
With that aside, the iPhone 4S generally does a better job. It's more flexible under a wider range of lighting conditions and you enjoy the benefits higher pixel density when you view the pictures under a fixed desktop resolution. This effect becomes more evident in a macro shot, at the bottom of this page.
No Zoom, Outdoors, Noon, Shady
Full-zoom, Outdoors, Afternoon Sun
