When you use the flash to take pictures of people, their eyes appear bright red in the shot.

Causes and solutions

Causes

When you use the flash to photograph people, their eyes sometimes appear bright red in the picture. This is known as the "red-eye effect". The pupils of the human eye adjust the amount of light that reaches the retina of the eye by contracting in bright conditions and dilating in dark conditions. If the camera flash suddenly fires in dark conditions, the pupils of the people being photographed cannot react quickly enough to prevent their retinas being photographed through the dilated pupils, resulting in the so-called "red eye".

Solutions

·	Set the camera's flash mode to "Red-eye reduction". In this mode, the flash fires a preliminary flash just prior to the main flash to make the subject's pupils contract. This prevents the subject's eyes from being photographed in a red-eye state by ensuring that little of the light from the main flash firing enters the eyeball and by minimizing the amount of light reflected back at the camera.
·	Have the subject face at an angle to the camera rather than directly along the camera's line of sight.