What causes the red eye effect in photos?
Red eye is caused by the pupil, or small black circle at the center of your eye. When you are in certain light, usually indoor lighting, your pupils are larger to allow more light into your eyes and give your retina more light to work with. However, when the flash occurs from a camera, the light reveals the back of your eye to the camera lense, causing the red we see. Red eye reducing cameras use a number of ways to prevent this, such as flashing a few times, causing your pupil to contract and shrink before the lense actually records the photograph. Incidentally, low light in a restaurant is used to cause your pupils to be enlarged, which is a type of body language, believe it or not. When your pupils are enlarged, naturally and not necessarily because of low light, it means you are happy with what you see, including the people you are looking at. In return, that person who is looking back at you subconsciously sees your pupils enlarged and recognizes that you like them. Therefore, by
