WHY RED EYE in photos?
Thursday, December 14, 2006

Have you wonder why there is Red Eye in photos taken at night?

This is a knowledge I've learned and would like to share to you.

Bright light comes into the eye, the eye tends to change its sizes of the opening, get shrink and become smaller. Light go to the back of the eye and then bounces back forward. So what happen is when there is a camera flash, when it is too fast or too bright, the people doesn’t have time to shrink the eyes, the light bounce to the back of the eye which is red. Its redness is because of the blood vessel. So, when you actually looking into the red eyes in the camera, you’re actually looking at the back of someone’s eye. Thus, you might notice that there are some digital cameras, which tend to reduce the red eye, they will have an initial flash to make the eye opening gets smaller and then another one, and then you won’t get as much the redness back.

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