If we look at a remote subject, normally on identical parts of mesh covers of an eye identical images will turn out; two images merge in one thanks to intervention of a brain. It is called as binocular sight.
In many respects an eye is more perfect, than the camera, but not in all. The camera gives the constant image of subjects with all its details, meanwhile as the image in an eye exists only during 1/16 sec. before emergence of the following accurate image. On a mesh cover often there are no details, and one image can be blocked and cover the following image. For this reason two honest observers can argue concerning the winner in races. Pictures do not possess such shortcomings and on it under such circumstances have advantage before the direct observer.
Both photos are projected at the same time on the screen by two various projectors. Both projectors polarize light so that the plane of polarization of one projector is perpendicular to the plane of polarization of another.
To make success in many sports and in other kinds of activity where big visual acuity is required, it is necessary to be able to estimate distance and depth and at the same time to see both eyes on the parties.
In case the subject comes nearer to an eye, forcing to increase distance to the image, the crystalline lens becomes more convex and thick. Its focal length thus decreases so that the distance of the image remains full and the image does not descend from a mesh cover (rice 2. This process yielding the same results as focusing of the camera, is called as accommodation.