what is field of view
Field of view, also known as horizon, field of view refers to the size of the range observed within a certain distance. The larger the field of view, the wider and more comfortable the observation range will be.
The field of view is generally represented by the horizon (observable width) at a kilometer and converted into an angle of view (angle of view). There are three common representation methods: one is to use the angle directly, such as angle of view: 9°; The visible range in meters, such as Field of view: 158m/1000m; the third is the feet at thousand yards used in some foreign countries, which is actually similar to the second, such as Field of vies: 288ft/1000y.
Generally speaking, the larger the aperture, the lower the magnification, and the larger the field of view, but the design of the eyepiece group is also critical.
Generally, you will see numbers like 7°, 8°… on the mirror body of the telescope, which indicates the angular field of view that the telescope can observe.
At the same time, the lens can also be classified according to the angle of view. The standard lens is about 45°, the wide-angle lens is about 60-80°, the ultra-wide-angle lens is about 80-120°, and the lens with a larger angle is called a fisheye lens.
Field of view is a very important technical index of binoculars. We often say that the field of view actually includes two Concepts: actual field of view and apparent field of view. The relationship between them is: actual field of view = apparent field of view / magnification multiple. The actual field of view is generally expressed by the angle or the field span beyond kilometers. With the help of trigonometric function, the Easy conversion. For example, the field of view mark of bergos 8×30 is 150/1000m, and the converted angle is 8.5 Degree, the apparent field of view is 8.5×8 = 68 degrees (there may be a little error).
The apparent field of view is the angular size relative to the human eye. Generally speaking, it is how large the field of view looks. because It is the direct feeling of human eyes, so it is more important for users. Unfortunately, manufacturers generally do not Mark this data on the product. Fortunately, it is very convenient to calculate with the above formula. Russian telescope One of the characteristics of is that all kinds of telescopes are in series. The apparent field of view of the same series is basically the same, such as Bago Shi series is about 66 degrees. About 72 degrees for high-power series and about 60 degrees for pocket series, all-weather series About 58 degrees. The wide-angle series (special product) is about 76 degrees. If the apparent field of view of the telescope is large At 60 degrees (there are other standards), it can be called wide angle.
Generally speaking, the larger the field of view of the telescope, the wider the scope of the observed object, and the more comfortable the observation experience is.
Post time: Jun-20-2022