When I don't know if my Apple Remote has batteries, I open the iPhone 4 camera and press the buttons pointing at it, I see a purple light that indicates that everything works correctly, it is infrared light. Take the test if you did not know.
When this infrared light passes through the camera filter it contaminates the channels, mainly the red channel, resulting in the colors being unrealistic. The new iPhone 4S, in addition to the 8MP and improved optics, is able to filter this infrared light, you can see it in the video compared to an iPhone 4.
The result to properly filter this light is that with the iPhone 4S we will get photos with much more realistic colors, especially in poor lighting conditions.
via |iClarified
Okay, although you can see that with almost any mobile camera, I remember doing it 3 years ago with my old Nokia N70, the lilac light was not visible, but it was distinguished, since it appeared as a white and blinking color in the infrared pilot of the command.
Good trick for those who do not know 😉
I already knew it, although I did not know the precision about the 4S. Likewise, this type of curiosity is cool 😉