To understand how binoculars work, it is important to understand that every pair of binoculars, from the ancient pirate’s telescope to the latest Zeiss binoculars, consists of three main components: the lenses, the prism system and the eyepieces. The object being observed reflects rays of light and they strike the lenses. Inside the binoculars, this light is corrected by the prisms and through the eyepieces, it hits the human eye. In the following, the individual components are described in more detail.
The lens is a lens which faces the object and through which the light is incident. There is a maximum of five pieces in a pair of binoculars. The image created by the interplay of light and lens is created on an intermediate level, is mirrored and upside down. That needs to be corrected.
In optical devices such as cameras or just binoculars, the lens, which faces the object to be viewed and through which the light is incident, called lens. More precisely, binoculars are also referred to as a lens system because binocular lenses consist of at least two lenses. For higher quality models, it can also be up to 5 lenses. The image that is created in this way is first mirrored and upside down. It, therefore, requires a mechanism to correct this.
Prisms are bodies of glass that can redirect light rays through multiple reflective surfaces. The prisms in the binoculars are arranged in such a way that they upright and mirror the image on the right and left. Two types of prisms are prevalent: roof prisms and Porro prisms.
In the Porro prism system, the prisms are set at right angles to each other and redirect the light rays several times. First, the picture is turned from left to right and then from top to bottom. These prisms are easy to manufacture and have the advantage that they consume little space in the binoculars. Their broad and short design, therefore, characterizes binoculars with Porro prisms.
In a roof prism system, the reflective surfaces resemble a house roof. It usually consists of 2 prisms and one has a roof edge. The reflection surface is usually provided with a metallic mirroring. Since roof prisms have higher manufacturing costs, roof binoculars are usually more expensive than comparable models with Porro prisms.
The eyepiece can be imagined in the function like a magnifying glass. It consists of 3-6 individual lenses. Through the eyepiece, the eye looks at the image erected by the prisms. When the image has been focused, the light rays pass through the eyepiece lenses exactly parallel. Wearers of glasses require special eyepieces that are more distant from the exit pupil.
Magnification and lens diameter
The most important key figures of binoculars are always given in the notation “ZahlxZahl.” The number before the x is the magnification or magnification factor. Typically, this is 8 or 10 – i.e., an 8-fold or 10-fold magnification. Binoculars for astronomy can also have significantly higher values (up to 50), compact binoculars or an opera-glass also much lower (e.g., 3x).
The code after the x indicates the lens diameter in mm. The larger this value is, the more light can get into the binoculars. Binoculars with a high objective diameter (56mm and more) therefore produce better images in low light conditions such as at dusk.
The digital binoculars
In addition to the components mentioned above, there are two sensors in the digital binoculars, which convert the image of the object under consideration into electrical impulses. After image processing, playback is performed on two electronic viewfinders, thus eliminating the connection between eye and subject.
To operate it needs electrical energy, which is provided by an accumulator. Upgraded digital binoculars can be with image stabilizers and digital photo and film functions.
Important key figures of the optical components
The key figures are given in the notation “number x number.” The first number that precedes x is the magnification or magnification factor. In most cases, a factor of 8 or 10 is used, which means that it is an 8x or 10x magnification. The number behind the x is the lens diameter in mm. A high value indicates that the binoculars can absorb a lot of light and can show good and clear images in low light conditions, such as at dusk.
How do binoculars work? This question is not so difficult to answer and I hope I could give my explanation here a first look at the function and structure of binoculars. If there are any questions, then there are more interesting articles here. Or you merely ask the problem in the comments.