تطور صناعة العدسات .. كتاب أسس التصوير الضوئي

Evolution of the lens industry

In order to overcome the aforementioned natural defects, it was necessary to make various improvements to photographic lenses - here is a description of this development:

(1) The first development: The first lenses used in photography were:

The simple uncorrected lens (Fig. 34), which is a grouped lens - is a single piece of glass, often in the form of a lens. Crescent or convex on both sides, and all of them suffer from the aforementioned defects. Given. Because of the defects that result when the rays pass near the periphery of the lens - such as spherical aberration, so it was necessary to add another lens, i. The rays passing near the center gather with those passing near the periphery, and it was noted that the amount of what the second gland does is sufficient for the required repair only, with the strength of these two lenses remaining positive and represented as a collecting lens, so the rays passing through the two lenses gather together at one point - thus ending the first development The second lens, called Single achromatic fens (Fig. 35), was formed. This single achromatic lens was able to resist spherical aberration and chromatic aberration.

(2) The second development: Since the last lens called the shromatic lens was unable to resist the two defects called: rrel & cushion distortion resulting from placing the diaphragm in front or behind the lens, so two groups of single achromatic lenses worked and were placed symmetrically. between them.


(3) The third development: is the manufacture of the Anastigmat lens (Fig. 37), which has finally covered the largest degree of lens defects, including the defect called astigmatish. It says here that it overcame the defects without mentioning that it overcame all the defects. Perhaps the reason for this is that it has not yet made what we can call a complete, completely free lens. The anastigmatism lens is an improvement in the manufacture of the last lens called. .Rapid-Rectilinear Liens, to which other lenses were added, between combined and separated, which were made with accurate calculation and placed at different distances. It consists of five or six pieces of glass, and they differ in their arrangement according to the different factories, according to their taste, which is suitable for the cameras that produce them, and according to the bony dimension of what is required!

This last type is what most factories are currently producing in micro-photocopiers - due to the provision of the Rapid Shutter. Shutter has been able to obtain images that need to be recorded at high speed with the use of .


A large opening without fear of defects that result from the use of the wide aperture of the diaphragm.

This telephoto lens is the only one that can be recommended for use in any resolution photography