The so-called red-eye effect is the result of people being positioned right in front of the camera looking straight into the integrated flash. The flash highlights the fine blood vessels at the back of the eyes as it is bounced off the eye's retinas. The ambient light in the room for frontal flash shots should be relatively bright. This is because the brighter the ambient light, the more the pupils will close down to conceal the blood-red retinas. Even with high ambient light levels in the room, pre-flashes emitted by integrated flash units cannot always guarantee that the natural color of a person's eyes is recorded. Although pre-flash causes the pupils to close prior to the actual flash, tests have proved that this merely diminishes and not eliminates the red-eye effect!
Eliminate red eyes with the appropriate Metz system flash unit. The reflector of the Metz mecablitz is positioned above the camera with the result that the frontal flash is not directed straight into the eyes but rather slightly above them. The Metz system flashgun can also be mounted on a bracket at the side of the camera, thereby once again avoiding the red-eye effect as the light no longer shines directly into the eyes. It is also possible to use bounce flash to produce a portrait. Indirect or bounce flash should always be used for small children, babies and animals as their pupils are far more widely open so that the red-eye effect is virtually inevitable!