What causes red eyes in a photograph and how can you reduce it without having to edit the picture afterwards.?

Question

Mine are always very bad.

Answer 1

Red eye reduction flash on the camera is ok, but it is a long drawn out process, and people tend to move before the picture is taken. What i do, and it is quite effective, is to 'diffuse' the flash by putting a cigarette paper over it. Give it a try. Rizla papers are only about 25p.
Good luck...

Answer 2

There is a time delay between the illumination of a flash and the exposure of the picture. This time is unnoticeable to us but it is there. Red eye occurs only when a flash is used. When there is very low light your pupils open wide, and when there is a lot of light, like sunlight or a camera flash, the irises make them smaller, but when the flash goes the speed of the exposure of the picture is much faster than the reaction time of the iris, so the pupil is still dilated in the picture, and the retina at the back of the eye is reflecting the light of the flash.

There is a way to reduce red eye. The first is to use a permanent light source for the picture, thus the pupils will contract before the picture is taken. Another is to use a double flash. The first flash makes the pupil contract and the second is to illuminate the picture.

But by far the easiest way to reduce this problem is to remember a simple law of physics - light travels (and reflects) in straight lines - so don't take flash photos directly in front of someone's face, and don't ask them to look into the camera. This kind of picture will give a more natural and enigmatic look, like they are just ignoring the camera.

Looking into the lens is fine on formal photos, but these would normally be in daylight or done by a pro with proper lighting.

Answer 3

I have to agree that "fhotoace" has supplied the best answer. Pros almost always use a device, such as an extension that holds the flash device to one side or above the camera equipment. In studio, they can use other, artificial light sources and reflective screens so that the subject is properly illuminated and none of the light is reflected from the back of the eyeball.

Since most people don't have this speciallized equipment, the double flash, red-eye reduction feature will help. Not having the subject looking directy at the camera will only offer some limited help. My first digital camera did not have a hot shoe attachement for mounting an extension device. Nasty, NASTY red-eye from my Fuji, even in subjects facing me in 3/4 view.

One other hint. The brighter the subject is lit from other, artificial sources, the smaller the subject's pupils. The smaller the pupils, the less red-eye. Add that to the double flash, not looking at the camera, etc, and you should see some significant improvement in the phenomenon.

Answer 4

Think of an eye as a dark round room with a highly white reflective projection screen in the back and some red smoke on the air. Include a window on the front

Whenever the light strikes the projection screen, a bright red light is seen... why?

The light coming to your eyes has the red smoke couloring what would look as a white light bulb... thje red comes from the blood in the inner eye.

There are many ways to avoid that, the most simple being having a flash shooting twice in sequence... the 1st makes the eye close the windows of your eyes - your pupile center- close a lot... so almost no inner red light comes out back. In the second flash, the eye is not ready, so you take the picture and the eye lens or window is still close....

In photography, that is called a closed aperture. It means the lenses closes a lot,,,, the same that happens whern you enter a highly illuminated room or try to watch directly the sun... your eyes close a lot....

Most current cameras shoot the flash twice in the red eye position...

More mature explanations at:

Link to :
http://science.howstuffworks.com/question51.htm

http://en.wikipedia.org/wiki/Red-eye_effect

Answer 5

Looking directly at the camera or it's flash causes red eye. It's actually the light reflecting off the back of the eyeball. Make sure the people you photograph don't like directly into the camera and it should make a difference.

Answer 6

fhotoacehas it right. Get that flash away from the lens, that's the only way to manage red-eye. Camera mounted flashes, even with red-eye reduction, are the cause of the phenomena. BTW, the aqueous humor and the vitreous humor (the 2 fluids found inside they eye) are clear, it is the retina at the back of the eye that is red due to the (blood) vasculature.

Answer 7

It happens when the flash of a camera is pointed directly at the eyes. If you don't have a camera that has red eye reduction you can just bounce your flash off a ceiling or soften the flash with a white paper or defuser.

Answer 8

Most cameras now come with built-in red-eye reduction. With digital cameras, just look through the settings, probably the flash settings.

Answer 9

reflection of the blood vessels in the back of your eyes.

cameras have this double flash that reduces red eye. sometimes the first flash tricks ppl and they blink or move

Answer 10

well i'm not sure what causes it, but on most newer digital cameras there is an anti-red eye setting.........see if ur camera has that setting and take advantage of it.....i always do!:0