Photographie and Sound health

The fact is that human eyes are also equivalent to a camera with an optical sensor screen and lens system. The pupil of the eye contains an organic fluid lens with adjustable focal length. Depending on the distance of the object we focus, its focal length directly varies. When any light falls on the adjusting tissues around the pupil, they just absorb all wavelengths from it and reflect a particular red wavelength alone which is negotiable to normal visible spectrum. Thus when we look into a normal person’s eyes, the pupil looks to be black in colour. But if immensely bright light falls on the pupil, the reflected red wavelength will be visible to our eyes. So when capturing human faces using a flash or with any bright light source behind the camera, the reflected red light will be recorded as the pupil’s colour in the image. This is known as the red eye reflection effect which makes the person in the image look as though he has got a monster’s eye. Presently almost all the latest DSLR’s as well as film cameras have got the red eye reduction option to prevent red eye effect by default when we capture the image. But, this has found to reduce the red eye effect up to a certain extent. So after the image is captured, image editing software like Photoshop has got the red eye removal tool which completely removes the red eye effect by itself and makes the pupil look black in colour.