what causes red eye in pictures taken by degital camra?

Answer 1

"Red Eye" is caused by the light from the flash,reflecting off the retina in the back of the eye. And the pupil dilating(getting wider) so you see the retina,which is red from the blood that is flowing through it.

Answer 2

Red eye happens with all cameras whether analog/film or digital. The condition is caused when the iris of the eye (human or animal) is wide open usually in a dark room -- the flash is at the same, or near the same axis as the lens. The angle of incident is the angle of reflection -- meaning the light from the flash is at the same angle as the camera lens; goes through the iris and hits the back of the eye reflecting back out at the same angle into the camera. The back of the eye is red -- hence red eye images. Raise the height of your flash relative to your lens or bounce the light and you will eliminate red eye. Also, if you raise the light level in the room, the iris in the eye adjusts to a smaller opening causing less angle for the flash to penetrate the back of the eye and bounce back out. Some flashes have a small continuous light source built in which is suppose to close down the iris of the eye before the flash goes off. At least in principle that is what is suppose to happen.

Answer 3

The cause of red eye is not specific to digital cameras, it's actually related to the size of the camera itself.

Red-eye is caused by the light of the flash being reflected off the blood vessels in the back of the eye and back to the lens. This wasn't a problem with older cameras because they were big and bulky and the angle between the lens and the flash avoided the red-eye effect.

When cameras got smaller, red-eye became a problem because the flash got closer to the lens. Professional photographers have their flashes mounted on brackets away from the camera lens to avoid this problem.

Red-eye reduction flashes a bright light in your subjects eyes to make their pupils constrict which reduces (but doesn't eliminate) red-eye.

My suggestion - don't use red-eye reduction. Because people always think the shot is done when they see the flash go off then they turn away before the picture is actually taken. Instead, use a regular flash and take the red-eye out with editing tools later. You're going to have to do in anyway with red-eye REDUCTION on.

Answer 4

this is caused by the flash going through the pupil, to the back of the eye, and giving you a reflection of the cones and rods in the back of the eye. although it may seem like the pupil is a black blob, it is hollow. you know how the eye doctor looks into your eye with a flashlight and sees the back of your eye? well thats basically what the flash of the camera. all you are seeing on red eye is the inside back of the eyeball.