Why do I always have red eyes in photos?
You probably know it. You are at a party, having a nice time with the family and you want to use this nice moment by taking a picture of the whole family. A few pictures are taken and when you look at them you see several people with red eyes in the picture… bummer! You try to take a few new pictures, hoping that these will work out, but every time there are people with red eyes in the picture. That’s a shame… How come people get red eyes in a picture, or more importantly, how do you prevent red eyes? We are going to explain that to you.
How do red eyes occur?
To see, you need light. Your pupils ensure that you get the right amount of light into your eyes. When there is a lot of light, your pupils become smaller to prevent you from getting too much light. Your pupils become larger when there is little light. This way, they can ensure that they can capture all possible light. This light enters your retina. Your retina is a small part at the back of your eye, which ensures that you can see clearly and perceive details.
But how do red eyes occur? Those annoying red eyes occur in photos taken with a flash. You use the flash in rooms where there is not enough light to take a photo. The fact that there is not enough light also means that your pupils are large. If someone is in the photo with red eyes, you are actually seeing the retina. That is the back part of your eyes. The moment the camera flashes, the light from the flash enters your eyes so quickly that your pupils do not have time to adjust. This overdose of light enters directly on your retina, which also contains a choroid. The red color is caused by the color of all kinds of small blood vessels that are located in this choroid. The light enters your retina and choroid and bounces back towards the camera, causing you to get red eyes. You can also see the red color of your blood vessels when you look into bright light with relaxed closed eyes: you can then see the blood vessels in your eyelids.
How can you prevent red eyes?
Of course, it is not possible to remove these vessels, but we would still like to get rid of the red-eye effect in photos. How can we solve this? Most cameras nowadays have a function to prevent red eyes. If you use this function, the camera flashes an extra time before a photo is taken. Thanks to the first flash, your eyes can adjust to the bright light by narrowing the pupils. This way, the large amount of light does not enter your eyes at once and you do not get red eyes. Another option is to ensure that you have enough light in another way to take a photo. For example, you can place extra lamps. If you do not have all these resources at your disposal, or if the damage has already been done; there are now enough (free) apps and programs with which you can easily correct red eyes.
