We’re not talking about red eyes caused by tiredness or over indulgence! We’re talking about “red eye” in photos – caused when using a flash.
What you’re seeing is the bright light of the camera flash being reflected off the rear of the eye. Because the light of the flash occurs too fast for the pupil to close, the light passes into the eye and reflects off the back of the eyeball – it’s this reflected light that the camera then captures.
Red eye only occurs if the flash is really close to the camera lens such as built-in flash or a flash mounted on the camera.
But how can you avoid it? Some cameras have a red eye reduction function. This fires the flash before you take the picture, causing the pupils to reduce in size, minimizing the red eye effect. Another method is to ensure that the flash doesn’t fire directly into the eyes of the subject, not really possible with built-in flash. Add on flash units can be angled to avoid this and better still is if the flash is “off camera” – this then needs a means to trigger it, either wirelessly or with trigger cables.
But you don’t necessarily need expensive add on accessories! A simple piece of white card or paper can be used to deflect flash light to avoid red eye – try it out, you might be surprised at the results you can achieve.