When the photonics are brought in discussion one of the first elements that come into the mind are optics. To be able to completely understand what are these and where are its present next lines will bring into the light the most important details.
An optical instrument is a asamblu of lenses, mirrors and apertures through which obtain images of various objects.
Some of the most known products that belong to this area and can be met in the daily living are: the photo camera, the microscope, the telescope and not the last, the binocular.
Regarding the first one, people always wanted to leave to the future generations a testimony of the most important events in their life. After testing the draw and the painting, at the end of the XIXth century they evolved to photography.
For this they discovered the photo camera, which is equipped with an adjustable diaphragm which creates a reversed image of an object, more or less clear and less lightened.
If this little machine receives an optic element, a convergent lens, the camera gives a clear, bright and overturned image. This is the working principal of the optic product.
The parts of a photo camera are represented by the lens, the visualizing system, the photographic film, the diaphragm, the shutter and the box. So, photo camera is an optical instrument used to create and record the image of an object on the film.
Another often used machine that belongs to optics area is the microscope. This allows the observation of the objects that are too small to be seen simply with the eye. The main parts of the microscope are the lens and the eyepiece. The lens, the part pointed directly to to object is a convergent lens or an aggregate of lens which has the role of an magnifier. So the microscope is the optical instrument that magnifies the very small objects.
The third optical instrument is the telescope which is used to increase very distant objects. In this area it can be mentioned the refractive telescope which uses convex lenses, to direct sunlight and to focus on it. This instrument has an early presence, since the end of the XIII century in Great Britain and then it become more known in The Netherlands.
The last mentioned optical instrument is the binocular. This has the role to bring closer to the eye the far away objects. It consists of two telescopes that can be focused in the same time.
Each telescope is equipped with a small concave lens called an eyepiece and with large convex lens called the objective Binoculars are classified by their ability to enlarge the power to capture light, such as 6x30, or 7x50 8x30. The first number represents the magnifying capacity and the second one the zoom lens diameter.
