One of the biggest annoyances when taking pictures is the common Red Eye problem. This can not be photoshopped out of most pictures, but it still is very common. Do you know what this is caused from? Probably not. The red eyes is caused from the light that is shone at a certain angle and gets reflected from the choroid. The choroid has many different blood vessels and because of this when light is shone to it, it appears red. To manually fix this when you take pictures, one can change the direction of the camera.