How do people get red-eye in photos?

Question

I took pictures on the last day of school, and I forgot about the red-eye setting.

As a result, some of my pictures came out with the red pupil.

I also noticed something.

Two of my friends both wear glasses. Alyssa took pictures with hers on, but Erin took hers off for the majority of the pictures. She came out with red-eye, and Alyssa did not.

So what causes red-eye, and why do some people get it in their pictures and others do not?

Here are some examples:

http://i196.photobucket.com/albums/aa292/MAXimize_1337/TwoForTheMoney.jpg

http://i196.photobucket.com/albums/aa292/MAXimize_1337/JustLookingEmo.jpg

http://i196.photobucket.com/albums/aa292/MAXimize_1337/HerLastPoseForTheDay.jpg

http://i196.photobucket.com/albums/aa292/MAXimize_1337/ErinLooksLikeAModel.jpg

http://i196.photobucket.com/albums/aa292/MAXimize_1337/NowTheyLookGreat.jpg

I am also very happy with this pictures, as it shows me with my best friend and my crush, but, sadly, it came out with red-eye.

http://i196.photobucket.com/albums/aa292/MAXimize_1337/SeanandErinTogetherForever.jpg

Answer 1

Red-eye occurs when the light from the flash enters the inner part of the eye and bounces back out to the camera. This usually happens with on camera flash as the light going to the subject is almost in direct line with the lens, the light comes back almosty directly into the lens.

This can be lessened/eliminated with off camera flash or bounce flash.

Also, red eye is more noticable when a subject is in a dark room. Why? Their pupils dialate(get bigger) to allow more light in. If the red-eye reduction flash is used, it sends out a pre-flash that closes the pupils down and lessens or eliminates the red-eye effect.

Answer 2

Red eye in pictures is the result of light reflecting on the retina of the eye.

The "red eye" feature on cameras is a little light on the front of the camera that causes the subjects pupils to contract (get smaller) and then it will reduce the chances of that reflection being caught on the picture.

Since your pictures are already taken, you can go to a photo kiosk (where print pictures) and scan the pictures that you have taken (if film) or insert your memory card (digital). Then there is an option to reduce the red eye just by touching a button (this may take more than one "click").

Some of this software is available for home use and usually comes with a digital camera. There are other software programs available that charge (fee varies). Currently, Wal-Mart (if you have one nearby) has a free software disc so that you can fix your pictures at home using the same kiosk technology...then you can fix them in the comfort of your home instead of the line waiting for kiosk. Then, if you prefer, you can send them via internet to Wal-Mart (Walgreens has this service also, I believe) and the pictures will be ready when you arrive.

Just remember (and not many know this...I didn't till it happened) to narrow down the area for the red eye as the program can alter other aspects of the photograph (keep it in the eye area. (i.e., fixing red eye and got the area box over bangs...resulted in blue and purple hair in that spot.)

Answer 3

Both previous answers are correct, however, the red is a reflection from the optic nerve. I'm assuming that these photos are done digitally? If that is the case, most programs from HP or Canon, to name two, have a red eye correction in the edit picture location. Simply put your cursor over the eye and make a circle over the red portion. Bingo, it's done.
The other way, actually, the old fashioned way of doing it was with touch-up photo dye. A fine tip brush, generally a 000 size is recommended, wet the brush with a little saliva and touch it to the eye. works like magic and looks like you're a pro. That's on the print, not a negative.
That's the way it used to be done in the old days before electronic imaging.
Hope I was helpful, Rick

Answer 4

Red eye is caused by the flash reflecting off the retina inside the eye. This happens because the flash is, A) brighter than average light and, B) because it's duration is so fast that the iris does not have time to properly dilate. Red eye reduction fires a series of flashes before the main flash to help the eyes adjust before the shot is taken. The person with glasses would not get red eye, or it would appear so because most of the light from the flash is being reflected off the lens of the glasses before getting through the pupils of the eyes.

Answer 5

What happens is the light reflects off the back of the retina, which is red. You're actually seeing through the lens of their eye. Since your friend Alyssa had her glasses on, the curvature on the glasses lenses was probably enough to keep it from reflecting there, especially if there is some correction for astigmatism (i.e., you see the light as a little bent--the object looks like it's not quite where it really is).

Answer 6

picasa is free and works good i do alot of photo editing with adobe but it is very pricey and picas is way easier to use