As a product that cannot be seen from the appearance but only from the clarity of the perceptual experience, the binoculars are very difficult to choose. The main points of the selection of the telescope:
1. Don’t pursue high magnification too much: 7-10 times is the best choice, if you exceed 10 times, your hands cannot be steady. Our troops purchase 7-10 times more.
2. Moderate caliber: Generally people like 40-50mm caliber, but if you want to go out and travel, it is recommended to choose 25-32mm caliber, so the volume is much smaller.
3. Eyepieces must be large: large eyepieces are much more comfortable to watch. In addition, from an optical point of view, a mirror with a large eyepiece will have more light entering the pupil, high light transmission rate and high clarity. In the market, the middle and low-end mirrors are mostly small eyepieces, and the high-end and top-end mirrors are all eyepieces.
4. The field of view must be large: a mirror with a small field of view looks very uncomfortable. The field of view is at 1000 meters, try to reach 110 meters or more, preferably 130 meters or more. The field of view is inversely proportional to the multiple and proportional to the caliber. But more importantly, it is determined by the design of the internal structure of the telescope. For mirrors of the same multiple and the same caliber, the field of view will vary greatly.
5. Clarity and high brightness: This needs to be felt by yourself, or by looking at the experience of others. The parameter index is difficult to see.
6. The choice of the optical structure of the telescope: Binoculars are divided into Paul type and roof type. The Paul type is a traditional structure. The advantage is that the optical structure is simple and the masculine is more masculine, but the volume is too large. Another point is that if it is a non-brand product, the repair rate will be higher. The roof type has a complex structure and small size. The disadvantage is that it will lose the light transmission rate. Therefore, the roof type requires better lenses and coatings to achieve the same brightness as the Paul type. High-end mirrors on the market are mostly roof-shaped. There are not many high-definition Paul-style telescopes on the market.
7. Try not to buy zoom telescopes: zoom telescopes such as 10-22X50 seem to change from 10 times to 22 times and have a wide range of applications. But the price of zooming is the reduction of clarity. The telescopes of the same brand and the same series of zooming magnification are at least one grade lower than the telescopes of constant magnification. The reason is the zoom, the internal design needs to increase the prism, lengthen the optical path, and greatly lose the light transmission rate. Another point is that the zoom structure cannot seal the telescope, so it cannot be filled with nitrogen and waterproof. These two reasons lead to a significant drop in clarity and brightness.