The cause of red eye in the photo

First, the "red eye" in the photo means that the pupil of the person or animal being photographed turns red, which is mainly the reason why the strong light of the flashlight shines on the capillary behind the retina in the dark environment. This phenomenon mostly appears on the models with a small included angle between the camera lens and the flashlight. For example, various lightweight digital cameras, for the sake of portability, design different elements in the camera quite compactly, so it is easy to produce red eyes in their works.

So how to get rid of red eye effectively in the taken photos, we can start from both soft and hard aspects:

1, camera function itself

Nowadays, many digital cameras have flash mode to remove red eye, which actually decomposes the flash process into two times. The flash will light up once after pressing the shutter to reduce the pupil to a certain extent, and then flash once when the camera officially records the photo to avoid the reflected red light.

2. Light source and main body

First of all, we can try to avoid shooting in dim light. After turning on the red-eye removal function, try to ensure that the subject's eyes are facing the flash, otherwise red-eye regeneration will still occur.

3, the choice of flash

On some digital cameras with slightly better performance, hot boots connected with advanced flash are reserved for users. When shooting, we can adjust the upward direction of the flash by 30-40 degrees, so as to generate brighter ambient light sources and reduce the probability of red eye formation.

4. Modify the picture with software.

There are many softwares that can remove red eyes. Taking PhotoShop as an example, we can use the ellipse selection tool to select the position of the whole black eyeball, and then click Adjust in the image menu to reduce the hue saturation. Finally, we can add the area around the black pupil to make the photo look more delicate and natural.

Secondly, since the invention of the flash bulb, red eye is a common phenomenon in photography. Red eye is caused by the light from the camera flash reflecting from the back of the eye (retina) of the subject and entering the camera lens. Because the retina is covered with blood vessels and appears red, the eyes of the subject in the final image are "red". Red-eye phenomenon does not mean that there is anything wrong with the subject's eyes.

If the flash is actually very close to the lens (almost all small cameras have it), the light emitted by the flash will directly enter the eyes and reflect back to the camera. In addition, if the subject's pupils are dilated (in a dark room), it will also increase the chance of red eye.

To reduce red eye, try the following techniques:

Keep the flash away from the camera.

Using off-camera flash (if possible) can prevent light from directly entering the eyes of the subject, thus reducing the phenomenon of red eye.

Backlight flash

Point the flash at the ceiling to soften the light and prevent it from reflecting directly from the eyes to the lens.

Enhance ambient light

Strengthening indoor lighting can narrow the pupil of the subject, thus reducing the phenomenon of red eye.

Use the "reduce red eye" mode on the digital camera.

In this flash mode, the flash flashes several times before the actual exposure, thus narrowing the pupil of the subject to reduce the red eye phenomenon.

Make the subject look slightly off the lens.

Looking at the side of the camera helps to change the angle of light reflection and reduce red eye.

Sometimes these techniques may not eliminate red eye. This situation can be handled by using the image editing software on the computer after taking pictures. Nikon View 6 has a powerful red-eye removal function, and the photographer can automatically or manually remove the red-eye phenomenon on the subject's eyes after taking pictures.

Red eye may appear when shooting animals, but the reflected light may be yellow, green or other colors due to different eye structures. The same technology mentioned above can also be used to eliminate these reflected lights produced by animal eyes.