Have you ever seen yourself in red eyes? Unless you view red eyes sexy, this will give you some simple tips to avoid that zombie’ eyes.
First, what is responsible for that phenomenon? You know light are electromagnetic radiations? There are seven types of them: gamma, x-ray, ultraviolet, visible, infrared, microwave and radio wave. The one who cause the red eyes things is visible.
Second, we’ll talking about our eyes. Our eyes are wonderful result from the evolution. Our pupil can constrict and dilate to allow light come in more or less. For example, under high sunlight, it constricts to allow small amount of light in. In another hand, there is a layer called Choroid, this layer contents large amount of blood vessels.
So, problem solve, when light from the flash light goes off, pupil don’t have enough time to constrict, large amount of light reflect by the Fundus (other layer of eye), with large amount of blood vessels, the light picked up by the lens of the camera appear red. Therefore, may I present you, zombie’s eyes (muha ha ha)
Okay, we already known the cause, now is the time for tips.
1. Use a camera has two flash before it takes the picture, this will give our pupil time to constrict perfectly.
2. Turn on more light so our constrict will also constrict
3. Move the flash away from the lens, this will increase the angle so light reflected by Fundus won’t go directly to lens.
This is the end of this topic ^~^
Source for more information: http://www.todayifoundout.com/index.php/2011/09/what-causes-red-eyes-in-photographs/