Preston Scott on why the iPhone 4S camera looks less purple than the iPhone 4 camera:
>When IR light is allowed to pass through to the sensor, the IR light contaminates the channels (mostly the red channel) with information that was not visible in the original scene. The result is an image with a color cast.
Great job explaining this — I had no idea the new IR filter was the reason for the more accurate colors in the 4S camera.