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How can lens glare be avoided? !

Glare is a common problem that photographers face from time to time. Sometimes this problem is simple and sometimes severe, but our knowledge of the cause of its occurrence helps us in a high way to avoid it.

When the film is exposed inside the camera, it is exposed, in principle, only to light reflected from the subject directly, and the light contrast of the image that reaches the film will be the same as that of the subject, but what happens in every camera, unfortunately, is that unwanted light or glare can reach To the film from different sources, as it reduces the optical contrast, and to an extreme extent in some cases, if the camera contains a colored film, the glare can cause the production of discrete colors.

In the appropriate circumstances, the glare can actually be seen in the viewfinder of the (SLR) camera. With the looks through it and the sun behind us, then turning to face the sun, we will notice that the light contrast in the image decreased dramatically and the shadows turned into a gray color.
This, and the most important source of glare, known as lens glare, comes from multiple reflections that come from the surfaces of the glass elements of the lens. Whenever there is a glass surface, a small percentage of the light that penetrates the lens is scattered. If the lens contains a large number of elements and many surfaces of the glass, It becomes possible
The scattered light is very noticeable.

Although some of this scattered light is reflected out of the lens, a large amount of it can still reach the film. Then, since there are a lot of reflections and reflections from many different glass surfaces, the scattered light reaches the film somewhat randomly. It falls on the film as a light flux of approximately equal intensity, as if the camera inside contains a small light source that begins to emit light whenever the shutter is opened.
As it happens in some circumstances that an amount of Glare from light sources located outside can appear as ghost images out of focus, and directly outside the limits of the field of view.

Additional glare may arise from reflections from the iris leaves of the diaphragm, inside the lens mount, or imperfectly polished and sealed edges of lens elements. Even the light reflected from the surface of the film on the blackened inner surfaces of some cameras can add to the general level of glare, especially when the bright sunlight hits the surface of the lens in an oblique manner. Bellows cameras are much less susceptible to this type of glare than modern hard-bodied cameras, because crinkle-fabric bellows can be completely non-reflective.

Although glare reduces light contrast in general, it affects shadowy areas in particular. And it is with the “color slide” film, it reduces color saturation and may give unwanted color smears because the glow is colored in a wide area with strong colors in the subject.
Ghost images are also common coming from the pupil of the diaphragm of the lens, or from light sources located directly outside the field of view.
The glare tends to increase with the light contrast of the landscape, and it often happens that the scene with bright highlights and deep shadows emits a large amount of glare. This may have its advantage, since the glare helps to mitigate the extreme contrast.

It has been customary to consider glare as a factor that reduces the optical contrast of the scene in the image projected on the film. If there is a subject with an radiation level of 100 to one and it gives an image of a level of 50 to one only, then the glare factor is two.
The glare factors can vary starting from approximately two and up to ten under unsuitable conditions. However, the values ​​depend on the conditions of the subject as much as they depend on the lens and the camera. Shooting towards the sun will raise the glare factor sharply.
Lens producers can limit the amount of lens glare in a dark room. They put a lighted board, like a light box, in front of the camera and turn off the lights in the room, after that they open the back of a camera so that the picture of the board is displayed on a screen installed behind the camera closely. Here, any light falling on the screen outside the image of the plate becomes a glare, and this glare can be measured with the appropriate equipment.
However, in everyday photography and in the study of color gradient products, glare should be evaluated by comparing the arc feature of a film and then drawing it for the conditions of glare and glare.

It is clear, however, that lens designers are making great efforts to reduce glare. Their most important technique here is lens coating.

Good blackening of the inside of the lens also helps keep glare to a minimum. Unfortunately, this non-reflective polish has never been produced yet.
It may happen to telephoto lenses, in particular, to suffer from a significant decrease in optical contrast.

A lens hood can make a noticeable effect, but it must block all light coming from outside the image area without blocking any light from the image itself. Once again, we find this ideal state difficult to achieve.

Surprisingly, dust is one of the major contributors to glow production. Hence, the surface of the lens should always be protected from dust. It is oily fingerprints in particular.
So that the fingerprint of one on the lens. You can make images lack contrast to the extent that they lose any value. If traces and paper intended for cleaning lenses appear, but the lens that is repeatedly cleaned even with the softest materials concerned soon accumulates pollution on the lens, this lens should be gently cleaned with fine scratches so that its surface becomes damaged. The result is a permanent increase in the level of glare.

From here, and to keep the glare at its lowest level and to maintain a full level of light contrast in our shots, we have to make sure that the fingers do not touch the lens at all ⏹