النظرية الأولية للتصوير الضوئي .. كتاب أسس التصوير الضوئي

The first Door

Initial theory of phototaxis

The initial idea of ​​the camera arose from the theory of the box with a hole. The camera in its simplest form does not go beyond being a tight box in the front of which is a pin-hole camera. . . The image is formed as a result of the exit of light rays from the objects that lie in front of the box and pass through the hole, and an image of the body is formed on the surface opposite the hole. The image is inverted, so the bottom of the body appears in the upper part of the image, and the bottom of the body appears on the left side of the image. It is possible to control the size of the image by increasing the extension of the box. If the distance between the object and the hole is equal to the image, then the dimensions of the image are exactly equal to the dimensions of the body (Figure 1).

And it is possible to estimate the dimensions of the image according to the following law: the distance between the hole and the image, the dimensions of the image = the dimensions of the object x the distance between, for example if we assume that the length of the object is 100, and that the length of the box (i.e. the distance between the hole and the image) = 10. cm, and that the distance between the object and the hole = 200 cm, then the length of the image is calculated as follows: cm

× 100 = the length of the image is cm, and we understand from the foregoing that the smaller it is, the smaller the distance between the hole and the image, i.e. the depth of the box, the smaller the image.

If we say from the length of the box, then the viewer is that the image increases in brightness despite not making any change in the width of the hole through which the rays pass, and this is self-evident, since the amount of light that formed the large image in the first case is the same as that formed the small image in the second case, so it is obvious that it increases The luminous intensity of the image if the light is concentrated in a smaller area.

In this case, the inverse square law applies, as the image luminous intensity is inversely proportional to the square of the distance between the hole and the opposite surface. (With the diameter of the hole remaining constant), the intensity of the image luminance increases and becomes (4 x).

Based on the previous observations, the researchers thought about making improvements to the box with a hole, as it was noted that the hole allows only a very small amount of light to pass through it, so if the hole is widened, the degree of clarity of the details decreases, as with its widening, we find that every point of light emanating from the object represents it on the image circle
mixed optical (Figure 2), and then they thought of replacing the expansion of the hole with a lens, and the placement of the lenses required making some changes in the shape of the box. The collection, in its primitive form, is full of visual defects, so it was necessary to make improvements in it, and it is necessary to control the time that it takes. In it, light passes through, so a shutter was prepared for the camera (Shutter), and thus improvements took place successively in the types of cameras until they reached the forms that we see recently. Allowed at the time when research was advancing to improve the machine itself was
We are conducting experiments and other research to find photosensitive surfaces that can
Record the photocopy on it. And the improvements also continued until it reached the form of progress that we see now