When you take pictures of pirates and they're ready for the heat of battle, often times their eyes would fiercely glow with the red fires of damnation itself! (Because pirates hate having their picture taken when they haven't had time to properly primp.)

But red-eye isn't a problem only associated with pirates; it can happen to anyone in situations where the flash is fired in a dark area.

Basically what happens is that the light from the flash goes directly into your eye and reflects off your retina (the back the of eye) which is nice and red. This reflected light is focused by the lens in your eye and is directed right back at the camera like a fricking laser beam. Pow!

What can you do to prevent this? Many things:

  1. Get more light in the room to cause your pupils to narrow. This allows less light from the flash into your eye and minimizes the effect.
  2. A variant of the previous item exists as a built-in feature on most cameras: anti red-eye mode. Make sure it's turned on. This fires a pre-flash before the exposure is made that causes your pupils to close before the main flash goes off.
  3. Don't point the flash directly into the eyes of your subjects. Not only does it increase red-eye, but it makes them see those spots that everyone hates. Of course, if you flash is fixed to your camera, it is tough to change the aim. In general, the farther offset the flash is from the camera lens, the better the results will be. Also, if your flash allows it, you might try angling the flash upwards to bounce it off the ceiling.
  4. Have the subject /not/ look directly at the camera so that the fricking red laser beams don't go right back into the camera lens. Have the subject look at something near the camera instead.
  5. Don't use the flash... try increasing your ISO, increasing the exposure length, or widening the aperture to get a good exposure without a flash.
  6. Post-process the final image. Photoshop and a lot of other types of software have a red-eye removal tool to get the red out. This is not cheating, provided you draw a goofy moustache on the subject at the same time.