why do we get red eye in photographs?

Answer 1

Red-eye is the reflection of the flash off the retina (the back of the inside of the eye). The light from the flash goes through the pupil and bounces off the retina, then back to the film.

Since we usually only use flash when it's fairly low light, our pupils are usually open wider at the time when the flash goes off, making this occurrence common.

Note that the color comes from the white light of the flash bouncing off the decided red-tinged retina (it's full of visible blood vessels).

Answer 2

"The effect is caused by the light from the flash reflecting off of the rear of the eye, the retina, which contains translucent blood carrying capillaries. Thus, the reflected light is red. The reflected light is passed back out of the eye and imaged by the camera. In dark surroundings, the iris of the eye, like that of the camera, opens to pass more light, thus the more pronounced the effect. Professional photographers deal with the problem by offsetting the flash source 6-10 inches from the plane of the camera lens. In this case, the reflected red light is offset so it does not pass through the camera lens. The amateur photographer does not want to carry around such a bulky contraption, so another solution has been developed. Unfortunately, it does not work very effectively. In this case just before taking the picture the camera sends out one or more preflashes in hopes of making the eye’s iris small enough that little light is passed back to the camera even though the flash and lens are very nearly on the same axis. Unfortunately, the preflashes are seldom strong enough or long enough to cause the iris to constrict before the main flash and may cause the person to blink at the wrong time. This feature often does considerably reduce battery life but little else.

What can the photographer do? Only use the flash when there is no other way to sufficiently light the subject. Turn on additional lights and open drapes. Remove lamp shades from lamps out of view of the camera. If you must use the flash, place a bright light source in the direction the subject will be looking, thus constricting the subject’s iris. Have the subject look at an object off camera.

If all of this fails to give acceptable results, then obtain a retouching program that has a good Red-Eye Retouching feature. "

http://www.tpcug.org/newsletter/nl_2002/april2002/red_eye.htm

Answer 3

The light of the flash occurs too fast for the iris of the eye to close the pupil. The flash light is focused by the lens of the eye onto the blood-rich retina at the back of the eye and the image of the illuminated retina is again focused by the lens of the eye back to the camera resulting in a red appearance of the eye on the photo. (This principle is used in the ophthalmoscope, a device designed to examine the retina.)

The effect is generally more pronounced in people with grey or blue eyes and in children. This is because pale irises have less melanin in them and so allow more light to pass through to the retina. Children, despite superficial appearances, do not have larger pupils but their pupils are more reactive to light and are able to open to the fullest extent in low light conditions. Many adults have lost the ability to fully open their pupils except through the use of drugs.

In many species the tapetum lucidum, a light-reflecting layer behind the retina that improves night vision, intensifies this effect. This leads to variations in the colour of the reflected light from species to species. Cats, for example, display blue, yellow, pink, or green eyes in flash photographs.

Answer 4

"If you use a flash in a dark environment, you often get a red eye effect. This is because the light of the flash is reflecting from the retina, which is covered with tiny blood vessels.

The more open the pupils are, the more red eye effect you get in your photos. Red eye is more pronounced in people with light eye color. It is also more pronounced in people with blond or light-red hair and in children."

Red eye reduction tips
1)If possible, avoid taking flash photos in a dark environment


2) Use red-eye reduction pre-flash

Many cameras have a built-in red-eye reduction pre-flash that helps reduce the incidence of red eye. Red-eye reduction works by having the flash shine a light into the eyes of the subject prior to taking the picture. This causes the pupil to contract.
However, you have to make sure the subject is looking at the camera. If not, this technique won't work. Also be wary of using red-eye reduction feature when not necessary, because it may cause your subject to blink.


3) Soften the light

Put a piece of tissue paper (prevent its direct contact with the hot flashbulb) over the flash to diffuse its brightness. Some photography shops sell flash diffusers. Use this method only on subjects that are close, because it reduces your flash range.

4)Take more than one picture

The first picture will cause the eyes of the subject to contract.

5) Position yourself near a light source

When your subject looks toward the camera, the nearby light will make his pupils contract.

6) Turn on more lights in the room

The brighter the room, the more your subjects' pupils will contract.

7) Ask your subject not to look straight at the camera.

Divert pets or babies so that they look away from the camera:

8) Use a special pen

Purchase an anti-red-eye pen from a photography shop. Draw over the red-eye on your prints to reduce red-eye effect.

9)Use image-editing software

Scan the photo into your computer and use image-editing software to correct red-eye. Many such software have a red eye reduction feature."

Answer 5

Because the camera is actually taking a picture of the inside of your eye, the red is your blood vessels. This only happens when you are looking directly into the camera.

Answer 6

not every race of people get red eye in photographs.

Answer 7

from the camera's flash. The light the flash emits is red and causes a reflection in the eye through the camera lens.

Answer 8

Drives me nuts!!!!!