Lecture-2

Cone of vision:

A perspective drawing will look correct only if our direction of vision, angle of vision of the subject is relatively fixed. This means a drawing with a limited field of vision. This field is usually called the cone of vision because of the infinite number of sight lines which radiate in a cone-like pattern from the eyes. In reality, these are actually the rays of light coming from the subject to the eyes. The angle of this cone is between 45-60 degrees as it is the capability of the human eye to clearly visualize objects inside of this range. A anything outside this range shall appear dizzy or not clear to the eyes. If a greater angle is applied in drawing, it is called a moving cone of vision – and the picture will be distorted.

Fig.91: General cone of vision (Distinct vision)

When we generally look at anything we normally concentrate on a succession of spots or centres of interest each of which is fixed by a sight line at the exact centre of the cone of vision. This line is usually called the centre line of sight of the centre of the cone of vision. When we look through a telescope or hold a pencil at such an angle that it appears to be a point it is actually located at the centre line of vision.

Fig.92: Angular limit of human vision across vertical order.

Fig.93: Angular limit of human vision across horizontal order.