Infared lenses look almost like black plastic to human eyes.
Bob
On my Kodak DX7630's external AF sensor, there seems to be a little piece of plastic INSIDE the sensor that partially blocks one of the two "bulbs", but I am not experiencing any focusing problems.
Should I get this problem fixed, or is this supposed to be there?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic