Short About Focusing Screens
Focusing screens are needed to facilitate the manual focus. Now, in the age of autofocus lenses have already forgotten about them, but in the past, almost all cameras have a focusing screen. Nowadays, they are relevant among fans of manual lenses, which concern me.
The standard focusing screen on modern DSLR cameras designed for autofocus lenses, and focusing manually, it is very difficult to catch sharpness quickly.
The Principle of Focusing screens
The principle of the focusing screen is that the matte surface of the objects in the field is even sharp, and what is out of focus, to become more blurred. This makes it easier to see which object in the field.
Photographers understand this principle, began to apply it. Initially focusing screens consisted only of matte glass, but more for their greater convenience and added a circular area, consisting of microprism and a split image rangefinder.
For example focusing screen from camera “Kiev 19” includes a matte glass, disc with microprism and a split image rangefinder. This gives the photographer to focus on any convenient method in his situation. Also, when the sharpness is, all three indicators will testify about it. This approach makes fewer mistakes.
There are different methods to facilitate manual focusing. For example, in older models, Nikon has audible confirmation of focus. Also on all cameras Nikon, in the lower left corner there is a green dot, which is lit when the subject is in focus. There is still a microchip Lushnikova (dandelion Lushnikova), which provides audible confirmation of the focus on younger models.
Somehow accidentally on the forum, I read about the existence of focusing screens. I have researched this topic and found that they produce only a few firms.
The most reliable reviews on American KatzEye, but the cost of their screen for my model is 160 dollars plus shipping. There are Chinese, they are cheaper, but the reviews about them are not very good.
And as an alternative, people use the focusing screens from old SLRt cameras. This method is the cheapest but needs a bit of improvement. I chose the third option. The process itself is described here.
Is it necessary focusing screen?
In most cases, yes. But he does not fit all. So, if you have good eyesight and you can easily distinguish the focus of an object or not, you, he may not need it. For example, my brother loves when he clean the viewfinder, without auxiliary circles and wedges, and mistakes like not complain.
There is also a disadvantage of focusing screen. When you close the aperture more than 5.6 microprism and split image rangefinder are darken, and to direct them sharpness becomes more difficult.