Why is there light in my eyes when I shoot with a flash?

The phenomenon of "red eye" is that when a person is photographed with a flash at night or indoors, the pupil of the person in the photo is red because of the reflection of the blood vessels in the fundus of the subject, which looks like the eyes of a rabbit. The main reason for the formation of red eye is that in the dark environment, the pupil of the human eye will actively enlarge to meet the needs of observing the environment. At this time, if the optical axis of the flash and the camera lens is relatively close, the strong light of the flash will be reflected to the lens through the human fundus. Because there are abundant capillaries in people's fundus, these blood vessels will be irradiated by strong light to form red spots, thus forming red eyes.

There are many ways to prevent "red eye":

1. appropriately increase the distance between the flash and the optical axis of the lens.

The greater the distance between them, the less likely it is to appear "red eye". For example, portable digital cameras are prone to red eye when shooting with built-in flash, while digital SLR cameras with independent flash are less prone to red eye.

2. Use the red-eye prevention function of the flash.

At present, general digital cameras (including advanced external electronic flash) have red-eye prevention function, as long as the red-eye prevention function is preset when shooting people. The camera will pre-flash several times before the official flash. Through pre-flash, the pupil of the human eye will be narrowed, thus reducing the phenomenon of red eye. However, this kind of shooting consumes a lot of electricity, so it should be used with caution in important shooting occasions with limited endurance.

3. Let the subjects see brighter objects.

When shooting a person, it is very beneficial for the subject to look at brighter objects. Even if the flash is not used, it can add light spots to people's eyes and make them more energetic. In a dark environment, using flash photography, such as people staring at a bright light window, can narrow the pupil and avoid red eye.

4. After the software is eliminated.

Don't worry if you find the subject has red eyes after shooting. You can use special software to modify the eyes, you can use the "airbrush" in the toolbar in Photoshop to change the color, you can also use the "copy stamp" to modify, and you can also copy the black eyes with right angles to cover the red eye. As long as the patient and meticulous operation, it can be seamless.