Select the binoculars in the market, the first to master some basic knowledge of binoculars , this article slightly Chen just a little, in order to provide reference for readers
Basic knowledge of the binoculars
The type of telescope (Porro Prism vs Roof Prism)
Binoculars are divided into two categories: porro Prism (Poof Prism) and Roof Prism (Roof Prism).Porro prism simple structure, light transmittance is higher roof type, at the same level as the distance between the lens wide, images from the rich stereo feeling, and due to the low technical requirements, price cheaper.Roof prism is relatively more complex structure, high precision and not easy to manufacture, cost and price are higher.Roof prism of two groups of prism in alignment design, make its narrow size, feel better, good sealing performance.Through constant innovation, at present, the focus of roof prism is porro prism much shorter.
In general, if the recent focus (4 m) there is no requirement, can choose according to individual be fond of freedom, but if the demand is higher, the telescope roof prism is wise choice.The appropriate ratio (between 8 ~ 10 times)
Telescopes are marked on the "10 x 42" and other words, including 10 representative ratio, 42 on behalf of the diameter of the objective.The indicators can be measured, such as using the 10 times of the telescope of a 100 m place, just as with the naked eye at 10 m watching the bird.People often ask: "how far this telescope can see?"In fact this is a can't answer the question, because in different objective conditions will produce different results.Such as in fog day can only look at 2 m, but it can see more than 500 m in sunny days;The dawn and the sun is shining, where the sun rises, the situation will be greatly different at noon.
And the smaller the ratio, the greater the Angle, the search target is more difficult;But the high ratio is influenced by trembling hands clarity.If used on shaking, telescope ratio should not be more than 7 times, otherwise you won't see the target.When the light is very sufficient, ten times more than 8 times see clearly;But at the time of insufficient light, such as in the evening, instead of eight times more than 10 times to see details, therefore, should not blindly pursue high ratio and ignores the clarity.
In general, handheld use telescope, ratio should not exceed 10 times, and eight times and 10 times is now the most widely used ratio.Objective (should be somewhere between 30 ~ 42 mm) in diameter lens diameter size effects directly into the light, so the larger the diameter, the better.Especially in comparative and intense light and shade, twilight, cloudy conditions, the larger the diameter, the higher into the light, the eyes can see more details.But the diameter, the greater the telescope will be heavy, long time use easy to tired, and therefore should be in accordance with the personal fitness choose as far as possible big diameter of the objective.But with the telescope price also with objective is proportional to the diameter, the bigger the diameter of the objective, the higher the price.
Field (bigger is better) telescope field refers to the 1000 m when can see the scope of the general cases, the field width should be higher than 104 m, the 6 degrees.Field of view, the greater the search target the sooner the easy, long time watching will be more comfortable.But the field, the greater the edge distortion and fuzzy, the worse the more complex the aberration correction will be difficult, the high technology needed and the cost is.Poor technology manufacturers can only production field of smaller telescope, so view size is a measure of quality measure telescope.Like swarovski EL8 x 32 telescope view will reach 8 degrees (140 m / 1000 m), has reached a very high standard.
The more natural color fidelity (better)
High quality telescope must faithfully reflect the scene primary colors and color saturation.Some manufacturers in order to increase the brightness of the telescope, increase or decrease a Duan Guangbo painstakingly, causes distortion phenomenon, make the scenery bluish or reddish.Here provides a simple selection method: look at telescope objective, if the objective lens appears red, on behalf of the red light is reflected, not into the telescope, the image of this kind of circumstance to see can slant blue, white is no longer white, always look unnatural and uncomfortable.On the contrary, if the objective reflection of the present is not obvious and it's soft, represent the vast majority of light has entered the telescope, amplified into people's eyes, again after such a telescope image the most natural, high fidelity.
To achieve high fidelity effect, coating technology is very important.Swarovski, for example, after adding multiple patent coating on the surface of the lens and prism, the light reflection from 4% ~ 6% to 0.2%.Due to light by the eye through the lens telescope before, after 10 multiple reflection and refraction, multi-layer coating will light transmittance sharply increased from 60% to 93%, make the image more clear, lies.Considering optical performance
Considering optical performance
Much stronger than the telescope for outdoor use, protective plastic shell is not strong, easily because of temperature change is too big lead to shift prism group, and eyes optical axis parallelism as long as the slightest deviation, use time longer would make eye fatigue, and even headaches and vomiting.So when buying a telescope must try, look and feel comfortable is the most basic requirements.Swarovski binoculars are all made of metal shell, strong and durable: outer wrapped up with rubber, besides can prevent slippery, collision, can be absorbed by has the human ear can't identify the parts of high frequency noise, prevent for birds or animals of the unseen.Don't pick in the midday sun telescope: at noon the light is enough, it is difficult to discern the stand or fall of telescope.So, when is the best time to choose and buy telescope should?The answer is - dusk.Only when the light faint was able to discern the telescope's good and bad.To see a see backlight: good telescope under the backlighting can also present the color of the object clear and perfect, will not let a person feel dazzling, also won't object to present a black, also does not have a white mist.