There are a wide variety of binoculars on the market. Their appearance, size, price and purpose are different. Some are used for viewing scenery, sports competitions and theatrical performances, some are used for observing birds and other animals, and some are used for observing birds and other animals. For fixed-point surveillance (such as forests, electricity, public security departments, etc.), it is also used to appreciate the magical and beautiful celestial bodies in the night sky… If you want to buy a binoculars that suits you, you must know the following:
What does the number in the telescope model mean?
The binoculars sold on the market are marked with such numbers: “7*35”, “8*50”, “15*70”, etc. The number in front of the “*” represents the magnification (the above three telescopes The magnifications are 7, 8, and 15 respectively. The number after the “*” represents the diameter of a single objective lens of the binoculars (the mirror on the side of the observation object), in millimeters (the apertures of the above three telescope objectives are respectively 35, 50, 70mm). Similar numbers appearing in the telescope models also have the same meaning. For example, there are numbers “0735”, “0850” and “1570” in the models of the above three telescopes. There are also some higher-end variable magnification telescopes whose magnification can be continuously changed within a certain range. For example, “082450” means that its magnification can be continuously changed from 8 times to 24 times, and the objective lens aperture is 50mm; “206078” means that its magnification can be continuously changed from 20 times to 60 times, and the objective lens diameter is 78mm…
Magnification (magnification) and field of view
The magnification (magnification) of the telescope is the magnification of the opening angle of the target when observing through the telescope (in layman’s terms, it is the ability of the telescope to bring the object closer. For example, using a 7x telescope to observe an object at 700 meters is equivalent to using The effect of visual observation of an object at 100 meters), its value is equal to the ratio of the focal length of the objective lens to the focal length of the eyepiece. When the focal length of the objective lens is fixed, the magnification of the telescope can be changed by changing the focal length of the eyepiece. The field of view is the size of the range that can be seen through the telescope. The larger the field of view, the wider the observation range and the more comfortable it feels. The field of view is usually expressed in kilometers (observable width, in meters) or converted into angles. The size of the field of view is inversely proportional to the magnification. The larger the magnification, the smaller the field of view.
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