In the past I've used a camera to check to see if my TV remote control was working or not. I would point my camera at the IR emitter of my remote control and there would be a blinking light on the camera display. I just tried this with my iPhone 4s and there was no blinking light. For reference I grabbed my wife's iPhone 4, and the light was displayed on her screen. So I guess this is visual proof the new camera in the iPhone 4s has an infrared filter.
Brice
Brice