دوائر الاختلاط .. كتاب أسس التصوير الضوئي

Circles of Confusion

According to the first theoretical rules of lenses, the object in front of the lens has only one sharp image located at the distance of the focal length of the lens, or in other words, there are no points of light emanating from the object that appear in the form of a point in the image except what is located at the distance of the focal length of the lens, while the rest Its image comes out in the form of mixed circles of light on the surface of the Hasbas board

The plane h_ is the plane on which the distance is set
Flat h' - represents the sensitive film, and the rays emitted from any light point on the surface are collected on the film h in the form of a sharp light point.

Distance BD: It is the distance whose image appears on the film with acceptable details. This is even though the light points emanating from this region are not represented by the image on the surface C as points of light completely, but rather mixed circles of light: circles of confusion, except that these circles are small in size in a way that can be bypassed. Therefore, the image of this region on film C is considered to be of acceptable detail.

distance ab
and distance d e
The light points emanating from these two regions appear as large mixed light circles; There are no points of light like it on the surface of the film, and the image of what is covered by this distance is mixed with each other in a great way, and the details are not sharp.
It appears to us from the foregoing that the mixing circle is what determines whether the image is or not. If the mixing circles are small, we express the image as having sharp details, and if the circles are large, then the image is not sharp in detail. considered a circle. Mingle big or small?