When analyzing the term binocular one discovers that it is a compound word that results from the union of two Latin words: binus (translated into Spanish as “double”) and ocularis (interpreted as “ocular”). The concept, therefore, refers to that which demands the attention of both eyes at the same time.
The term, as many of you will know, is intended to identify the optical element that allows you to look or observe simultaneously with both eyes. Binoculars are also known as binoculars or binoculars and its function is to increase the image of objects not so close that can be seen through the device.
The telescope and the monocular they are other optical instruments that enlarge images. The main difference with binoculars is that they generate the effect of stereoscopy (that is, they recreate the illusion of depth in the image). Stereoscopy is achieved thanks to the fact that each of the two tubes of the binocular contains different lenses and a prism, which allows you to enlarge the image for each eye in particular.
The light it passes through the series of lenses until it reaches the prisms, which are responsible for placing the image in its correct position through the principle of total internal reflection. This also differentiates binoculars from telescopes, which display the image reversed.
It should be noted that there are multiple models and types of binoculars. Most of them offer the possibility for the user to adjust the separation between the eyepieces for greater comfort. Binoculars also often have a diopter correction ring (installed in the right eyepiece to improve focus) and include focus wheels.
The magnification level of the images and the diameter of the objective is measured in millimeters and is expressed as a pair of digits that are separated by a X. Binoculars 14 × 60For example, they offer a 14x magnification level and a pair of 60mm diameter lenses.
Tips for choosing the ideal binocular
To find out what the magnification of a binocular is, just pay attention to the first figure that appears in its measurement; if you have a 10×50 device, it means you can enlarge or reduce the size of the object up to 10 times. That is, if with it we are going to observe the Moon, which is at a distance of 384,000 km, we will see it as if we were at a difference of 38,400 km.
Regarding the Visual field, this data indicates the angular size allowed by the gadget. If you have a 7º field of view, you can see objects that may be within a 7º diameter. It is worth mentioning that some models refer to the visual field in feet or meters; that is, in a straight line. Both values are important and that is why it is good to know how much of one is equivalent to one value of the other. For example, if the binocular has a field of view of 373 feet, its degree equivalent is 7.1º. It is calculated through the following formula: C (field of view in degrees) [º] = Arctg (L (linear visual field) / 914m (linear field constant).
Other fundamental aspects to take into account when choosing the ideal binoculars are:
* The opening: indicates the amount of light entering; the greater this, the more detail can be achieved in visibility;
* The enlargement: indicates the level of zoom in or out that can be achieved; the higher this value, the smaller the field of visibility. This detail should be considered taking into account the opening; it is necessary to find a balance between both values;
* Exit pupil: refers to the diameter of the beam of light emitted by each eyepiece and is measured in millimeters. It is extremely important to take it into account, especially for binoculars that will be used in night observation;
* Eye and focus adjustments: those devices that are more malleable and that allow customizing the focus and the observing eye, are the most recommended, due to their versatility; however, it is always advisable to be clear about the use of the binocular to know which device to choose.