ShengTu Optics
Member
1. You need to know your purpose in advance: whether it is watching performances or competitions, outdoor hiking, bird watching, or balcony viewing. Different purposes have different requirements for the volume, weight and multiples of the telescope.
2. You need to clearly tell us your psychological price: the same specifications can cost from tens of yuan to thousands of yuan or even more than ten thousand yuan. Products of similar prices may have large differences in quality. Only by clarifying the price can we make the best recommendation.
3. Believe in the recommendations of veteran players: veteran players’ experience is gained through spending a lot of money and time. If you don’t want to pay tuition, you must listen to veteran players. After all, you are just daydreaming in front of the computer, while veteran players have actually played for a long time and used many products.
4. Don’t choose products that are too obscure and no one cares about: The chance of a novice being able to discerningly select a high-quality product that has not been discovered by countless players among the countless products is almost zero.
5. Don't replace thinking with desire: I want high magnification, variable magnification, a compact camera, I want to see clearly XX 10 kilometers away, etc. Desire must obey reality - basic physical laws and how high a price you can afford. Fantasy is meaningless.
6. Don't use intuition to replace thinking: for example, high magnification is better than low magnification, variable magnification is better than fixed magnification, military is better than civilian, imported brands are better than domestic brands, products with large sales are better than products with small sales, big brands are better than niche brands, etc. Don't jump to conclusions, look more, ask more, and think more.
7. Resist temptation: Many low-end Taobao brand telescopes are overrated in their product descriptions, and are unmatched in the world. Just think: If they are really so good, why are they sold so cheaply? Is it wrong that the ancients said that the buyer is always less skilled than the seller? Has the economic law of "you get what you pay for" also failed?
8. Learn to compromise: Make reasonable choices among factors such as price, volume, weight, multiples, caliber, and brand. Don’t expect everything to be as you wish. Only a liar will tell you that his product meets all your requirements.
9. Read posts and discuss in different youtube, post bars, forums, etc., and verify each other's rational analysis. Read less about the product descriptions written by merchants, which are full of misleading information that seems to be true, and newcomers are easily fooled because they lack the ability to distinguish.
10. Learn to trust. Not everyone is a liar. There are always people who are trustworthy. What they say may not be pleasant to hear or what you wish. It is just that the truth is hard to hear. Be open-minded, let down your guard and communicate with everyone. You will gain more.
What does something like 8X30 mean?
The specifications of binoculars are often expressed with numbers like 8X30. 8 means that the binoculars have an 8x magnification capability, which can bring the distance of the observed target 8 times closer. For example, if a target is 800 meters away, the image size is the same as that of a target observed directly with the naked eye at a distance of 100 meters (due to atmospheric interference and the quality of the binoculars, the observation effect is not as good as that of a target observed directly with the naked eye at a distance of 100 meters). 30 means that the objective lens of the binoculars is 30 mm in diameter. The larger the number, the brighter and clearer the image, and the more comfortable the observation, but the corresponding size, weight and price of the binoculars will increase.
Is the higher the multiple, the better?
Most people intuitively believe that the higher the magnification of a telescope, the better. This is a very wrong concept. Due to the influence of hand shaking when holding a telescope, as well as the limitations of the volume, weight and atmospheric stability of the telescope, a handheld telescope is generally more suitable for 7-12 times. The telescopes used by the army are basically 7 or 8 times. The mainstream top-level handheld binoculars are basically 8-10 times. Unless anti-shake technology is used, such as CANON and FUJINON's anti-shake telescopes, the magnification will be adjusted to 10-18 times. Many manufacturers take advantage of the psychology of ordinary people who like high magnification and deliberately falsely mark the magnification of telescopes to cater to the desires of consumers. The quality of such non-serious products is also difficult to guarantee. It is recommended that you do not buy them.
Why don't we recommend zoom binoculars?
In the imagination of many newcomers, it would be great if the image in the telescope could be large or small, far or near! In fact, this is just a beautiful imagination! From an optical point of view, it is difficult to make a zoom product. Friends who play photography know that the effect of fixed focus lenses is better than zoom lenses. Low resolution, small field of view, and distortion are common problems of zoom. Moreover, binoculars are two sets of zoom eyepieces linked together, and the mechanical structure is also very complicated. In particular, the positioning of variable-magnification binoculars is generally low, cost control is harsh, and the material and precision of parts are low, so the common optical problems are more serious, the structural failure rate is also higher, and the optical axis is almost more or less offset. Therefore, we never recommend variable-magnification binoculars, nor do we sell variable-magnification binoculars. For variable-magnification monoculars, the structure is much simpler, there is no linkage problem, and there is no problem of non-parallel optical axis, so even very cheap bird-watching mirrors, such as Gaomu bird-watching mirrors, are acceptable.
Which multiple is more appropriate?
Generally speaking, a handheld binocular with a magnification of 7-10 times is sufficient. A magnification that is too high will bring many problems (large image jitter, small field of view, low brightness, etc.). Serious brands generally do not have very high magnifications! Many Taobao brands like to mark dozens or hundreds of times, which are all deceptive. If you can use a tripod, the magnification can be higher. A single tube can reach 20-70 times, and a binocular can reach 20-30 times. Note that the magnification must be matched with the aperture. Simply increasing the magnification without increasing the aperture will result in a very poor imaging effect.
Which caliber is better?
The larger the aperture of the telescope, the better the observation effect, but the more expensive it is. The larger the size, the heavier the weight. The smaller the aperture, the worse the observation effect, but the smaller the size, the lighter the weight, and the easier it is to carry. Generally, 20-50mm diameter binoculars are selected for handheld use. If it is mounted on a tripod, the diameter can be 50-100mm.
Common specifications and applicable scope
8X20, 8X25, 10X25 - pocket-sized, suitable for carrying around and outdoor concerts during travel, but not suitable for occasions with low light levels
8X30, 8X32——Moderate type, suitable for daily use, taking into account both effect and portability
8X40, 8X42——Full-size model, very comfortable to observe, suitable for different lighting environments, slightly larger in size and weight
7X50——Low-light/Navigation/Stargazing. This model has excellent observation comfort, good imaging stability, and high brightness in low-light environments. However, it is bulky and heavy, so it is not suitable for daily use.
10X50——Balcony type, this specification has high magnification and high brightness, but the image is slightly jittery, you need to find an object to lean on when observing, the size and weight are relatively large, not suitable for outdoor use
12X60, 15X70——Balcony reinforced type, large aperture, high magnification, large shake, better observation effect with tripod, large size and weight, not suitable for outdoor use
20X80, 25X100——Outpost type, with extremely high magnification and large caliber, the strongest long-range observation capability, must be used with a tripod, and is also very heavy and large in size
Should I choose a Porro prism telescope or a roof prism telescope?
The advantages of Porro prism telescopes are low price and good effect, but the volume and weight are about 40% larger than the roof prism telescope of the same specification, and the minimum observation distance is far, so it is not suitable for bird watching and other occasions that require close observation.
The advantages of roof prism telescopes are small size and weight, good portability, short observation distance, and suitable for bird watching, but the technical requirements are high, and cheap models cannot obtain good image quality.
Generally speaking, when the budget is less than 300 yuan, unless size and close-range observation are particularly emphasized, Paul telescopes are recommended first. If the budget exceeds 300 yuan, you can consider a roof prism telescope. If the budget exceeds 1,000 yuan, roof prism telescopes are mainly recommended.
Choose binoculars or monoculars?
In terms of observation effect, binoculars of the same specifications are much better than monoculars. The image is three-dimensional, the resolution is higher, the image is brighter, and the observation is more comfortable. However, the volume and weight of a monocular are more than half that of binoculars of the same specifications. Monoculars are easier to achieve high magnification, such as bird-watching telescopes. Therefore, for handheld telescopes, binoculars are recommended for better effects, and monoculars are recommended for lighter volumes. If you can use a tripod and want to achieve high magnification effects, a monocular bird-watching telescope is recommended.
How many ways are there to express field of view?
Common methods include degrees, xxx meters/1000 meters, xxx yards/1000 inches, etc. Taking 125 meters/1000 meters as an example, it means that when a telescope is used to observe a target 1000 meters away, the range that can be seen is a circular area with a diameter of 125 meters. In addition, taking an 8x telescope with an actual field of view of 7.5 degrees as an example, although the actual observation range is only 7.5 degrees, because the telescope has an 8x magnification effect, the apparent field of view is 7.5x8=60 degrees, and the observation does not feel cramped. Telescopes with an apparent field of view of more than 60 degrees can be regarded as wide-angle telescopes.
What is the algorithm and meaning of exit pupil diameter?
Exit pupil diameter = telescope objective lens diameter ÷ magnification. For example, for an 8X30 telescope, the exit pupil diameter = 30 ÷ 8 = 3.75 mm. If the exit pupil diameter is less than 3 mm, such as 8X21 and 10X25, it is generally only suitable for observation in a well-lit environment. If the exit pupil diameter exceeds 5 mm, such as 8X42 and 7X50, it can be observed in a dim light environment (dusk, dawn, moonlit night, etc.). The telescope cannot be observed in a completely dark environment.
What is the difference between a Porro prism and a roof prism?
If there is no prism to transform the image, the image we see is an inverted image. The prisms commonly used in handheld telescopes are divided into Porro prisms and roof prisms. Porro prisms have good imaging effects and low prices, but they are large in size and weight. Roof prisms are small in size and weight, but they have the disadvantages of double aberration, phase difference, and inability to fully reflect. These defects need to be overcome by using high-precision prisms, phase films, and high-reflection films, resulting in a relatively expensive price for telescopes.The left side is the "Paulo prism" and the right side is the "roof prism"
What is the difference between BAK4 and BK7 ?
Porro prisms often use two kinds of lenses, BAK4 and BK7. The former has a high refractive index and can achieve total reflection of the entire field of view, while the latter has a low refractive index and the light at the edge of the field of view cannot be fully reflected. Therefore, the imaging effect at the center of the field of view is the same, while the image at the edge of the field of view will be darker with BK7 than with BAK4. However, the human eye's attention is mainly focused on the center of the field of view, so the imaging effect of the two prisms is not much different. The factory price of BAK4 prisms is more expensive than that of BK7, so low-end Porro prism telescopes often use BK7 prisms. Hold the telescope, keep your eyes 30 cm away from the eyepiece, and observe the shape of the exit pupil spot. If it is a bright circle, it means it is a BAK4 prism. If it is a circle with 4 dark corners, it is a roof prism. For roof prisms, it doesn't matter what material is used. Many roof prisms also claim to use BAK4 prisms, which are basically commercial propaganda, have no technical significance, and it is impossible to judge what material is used with the naked eye.
The left picture shows the BAK4 prism, and the right picture shows the BAK7 prism
What is the function of anti-reflection coating?
There are multiple sets of lenses inside a telescope, and each set of lenses has two reflective surfaces. If there is no anti-reflection film, at least 50% of the light will be consumed in the reflection on the lens surface, which will seriously reduce the brightness of the image, reduce the contrast, and make the image look foggy. Therefore, it is necessary to coat the lens surface with an anti-reflection film to reduce reflection. The most traditional anti-reflection film is a single-layer film, which reflects blue light, commonly known as a blue film. The anti-reflection effect of a multi-layer anti-reflection film is better, and the reflection is mostly green, commonly known as a green film. Based on this feature, many manufacturers intentionally manufacture low-cost single-layer green reflective films, commonly known as decorative films, which are harmful to imaging. Everyone must be vigilant. The color of the coating is not the key, the key is whether the reflected light is weak. The weaker it is, the lower the reflection and the better the anti-reflection effect.
What is the function of nitrogen waterproofing ?
Nitrogen-filled waterproof telescopes are filled with dry nitrogen. Moisture in the air cannot penetrate into the interior, and mold will not grow inside the lens. They can be maintained and used for a long time and are suitable for various outdoor activities.
Are military telescopes the best?
Absolutely not. Military binoculars are used in battlefield environments and mainly emphasize durability and high reliability. They do not require high optical quality and details. The so-called Type 62 military binoculars are not as effective as the Forester 8X30 standard version, which retails for 238 yuan. In the past, only the military was equipped with binoculars, and ordinary people could not afford them (you could only buy a Panda binoculars if you didn't eat or drink for half a year), so the myth of the good effect of military binoculars was created. In addition, with the development of optoelectronic technology, the role of binoculars in the army has continued to decline. If ordinary people do not have a love for military products and do not climb mountains and cross ridges every day, they should not buy military binoculars, which are extremely impractical.
2. You need to clearly tell us your psychological price: the same specifications can cost from tens of yuan to thousands of yuan or even more than ten thousand yuan. Products of similar prices may have large differences in quality. Only by clarifying the price can we make the best recommendation.
3. Believe in the recommendations of veteran players: veteran players’ experience is gained through spending a lot of money and time. If you don’t want to pay tuition, you must listen to veteran players. After all, you are just daydreaming in front of the computer, while veteran players have actually played for a long time and used many products.
4. Don’t choose products that are too obscure and no one cares about: The chance of a novice being able to discerningly select a high-quality product that has not been discovered by countless players among the countless products is almost zero.
5. Don't replace thinking with desire: I want high magnification, variable magnification, a compact camera, I want to see clearly XX 10 kilometers away, etc. Desire must obey reality - basic physical laws and how high a price you can afford. Fantasy is meaningless.
6. Don't use intuition to replace thinking: for example, high magnification is better than low magnification, variable magnification is better than fixed magnification, military is better than civilian, imported brands are better than domestic brands, products with large sales are better than products with small sales, big brands are better than niche brands, etc. Don't jump to conclusions, look more, ask more, and think more.
7. Resist temptation: Many low-end Taobao brand telescopes are overrated in their product descriptions, and are unmatched in the world. Just think: If they are really so good, why are they sold so cheaply? Is it wrong that the ancients said that the buyer is always less skilled than the seller? Has the economic law of "you get what you pay for" also failed?
8. Learn to compromise: Make reasonable choices among factors such as price, volume, weight, multiples, caliber, and brand. Don’t expect everything to be as you wish. Only a liar will tell you that his product meets all your requirements.
9. Read posts and discuss in different youtube, post bars, forums, etc., and verify each other's rational analysis. Read less about the product descriptions written by merchants, which are full of misleading information that seems to be true, and newcomers are easily fooled because they lack the ability to distinguish.
10. Learn to trust. Not everyone is a liar. There are always people who are trustworthy. What they say may not be pleasant to hear or what you wish. It is just that the truth is hard to hear. Be open-minded, let down your guard and communicate with everyone. You will gain more.
What does something like 8X30 mean?
The specifications of binoculars are often expressed with numbers like 8X30. 8 means that the binoculars have an 8x magnification capability, which can bring the distance of the observed target 8 times closer. For example, if a target is 800 meters away, the image size is the same as that of a target observed directly with the naked eye at a distance of 100 meters (due to atmospheric interference and the quality of the binoculars, the observation effect is not as good as that of a target observed directly with the naked eye at a distance of 100 meters). 30 means that the objective lens of the binoculars is 30 mm in diameter. The larger the number, the brighter and clearer the image, and the more comfortable the observation, but the corresponding size, weight and price of the binoculars will increase.
Is the higher the multiple, the better?
Most people intuitively believe that the higher the magnification of a telescope, the better. This is a very wrong concept. Due to the influence of hand shaking when holding a telescope, as well as the limitations of the volume, weight and atmospheric stability of the telescope, a handheld telescope is generally more suitable for 7-12 times. The telescopes used by the army are basically 7 or 8 times. The mainstream top-level handheld binoculars are basically 8-10 times. Unless anti-shake technology is used, such as CANON and FUJINON's anti-shake telescopes, the magnification will be adjusted to 10-18 times. Many manufacturers take advantage of the psychology of ordinary people who like high magnification and deliberately falsely mark the magnification of telescopes to cater to the desires of consumers. The quality of such non-serious products is also difficult to guarantee. It is recommended that you do not buy them.
Why don't we recommend zoom binoculars?
In the imagination of many newcomers, it would be great if the image in the telescope could be large or small, far or near! In fact, this is just a beautiful imagination! From an optical point of view, it is difficult to make a zoom product. Friends who play photography know that the effect of fixed focus lenses is better than zoom lenses. Low resolution, small field of view, and distortion are common problems of zoom. Moreover, binoculars are two sets of zoom eyepieces linked together, and the mechanical structure is also very complicated. In particular, the positioning of variable-magnification binoculars is generally low, cost control is harsh, and the material and precision of parts are low, so the common optical problems are more serious, the structural failure rate is also higher, and the optical axis is almost more or less offset. Therefore, we never recommend variable-magnification binoculars, nor do we sell variable-magnification binoculars. For variable-magnification monoculars, the structure is much simpler, there is no linkage problem, and there is no problem of non-parallel optical axis, so even very cheap bird-watching mirrors, such as Gaomu bird-watching mirrors, are acceptable.
Which multiple is more appropriate?
Generally speaking, a handheld binocular with a magnification of 7-10 times is sufficient. A magnification that is too high will bring many problems (large image jitter, small field of view, low brightness, etc.). Serious brands generally do not have very high magnifications! Many Taobao brands like to mark dozens or hundreds of times, which are all deceptive. If you can use a tripod, the magnification can be higher. A single tube can reach 20-70 times, and a binocular can reach 20-30 times. Note that the magnification must be matched with the aperture. Simply increasing the magnification without increasing the aperture will result in a very poor imaging effect.
Which caliber is better?
The larger the aperture of the telescope, the better the observation effect, but the more expensive it is. The larger the size, the heavier the weight. The smaller the aperture, the worse the observation effect, but the smaller the size, the lighter the weight, and the easier it is to carry. Generally, 20-50mm diameter binoculars are selected for handheld use. If it is mounted on a tripod, the diameter can be 50-100mm.
Common specifications and applicable scope
8X20, 8X25, 10X25 - pocket-sized, suitable for carrying around and outdoor concerts during travel, but not suitable for occasions with low light levels
8X30, 8X32——Moderate type, suitable for daily use, taking into account both effect and portability
8X40, 8X42——Full-size model, very comfortable to observe, suitable for different lighting environments, slightly larger in size and weight
7X50——Low-light/Navigation/Stargazing. This model has excellent observation comfort, good imaging stability, and high brightness in low-light environments. However, it is bulky and heavy, so it is not suitable for daily use.
10X50——Balcony type, this specification has high magnification and high brightness, but the image is slightly jittery, you need to find an object to lean on when observing, the size and weight are relatively large, not suitable for outdoor use
12X60, 15X70——Balcony reinforced type, large aperture, high magnification, large shake, better observation effect with tripod, large size and weight, not suitable for outdoor use
20X80, 25X100——Outpost type, with extremely high magnification and large caliber, the strongest long-range observation capability, must be used with a tripod, and is also very heavy and large in size
Should I choose a Porro prism telescope or a roof prism telescope?
The advantages of Porro prism telescopes are low price and good effect, but the volume and weight are about 40% larger than the roof prism telescope of the same specification, and the minimum observation distance is far, so it is not suitable for bird watching and other occasions that require close observation.
The advantages of roof prism telescopes are small size and weight, good portability, short observation distance, and suitable for bird watching, but the technical requirements are high, and cheap models cannot obtain good image quality.
Generally speaking, when the budget is less than 300 yuan, unless size and close-range observation are particularly emphasized, Paul telescopes are recommended first. If the budget exceeds 300 yuan, you can consider a roof prism telescope. If the budget exceeds 1,000 yuan, roof prism telescopes are mainly recommended.
Choose binoculars or monoculars?
In terms of observation effect, binoculars of the same specifications are much better than monoculars. The image is three-dimensional, the resolution is higher, the image is brighter, and the observation is more comfortable. However, the volume and weight of a monocular are more than half that of binoculars of the same specifications. Monoculars are easier to achieve high magnification, such as bird-watching telescopes. Therefore, for handheld telescopes, binoculars are recommended for better effects, and monoculars are recommended for lighter volumes. If you can use a tripod and want to achieve high magnification effects, a monocular bird-watching telescope is recommended.
How many ways are there to express field of view?
Common methods include degrees, xxx meters/1000 meters, xxx yards/1000 inches, etc. Taking 125 meters/1000 meters as an example, it means that when a telescope is used to observe a target 1000 meters away, the range that can be seen is a circular area with a diameter of 125 meters. In addition, taking an 8x telescope with an actual field of view of 7.5 degrees as an example, although the actual observation range is only 7.5 degrees, because the telescope has an 8x magnification effect, the apparent field of view is 7.5x8=60 degrees, and the observation does not feel cramped. Telescopes with an apparent field of view of more than 60 degrees can be regarded as wide-angle telescopes.
What is the algorithm and meaning of exit pupil diameter?
Exit pupil diameter = telescope objective lens diameter ÷ magnification. For example, for an 8X30 telescope, the exit pupil diameter = 30 ÷ 8 = 3.75 mm. If the exit pupil diameter is less than 3 mm, such as 8X21 and 10X25, it is generally only suitable for observation in a well-lit environment. If the exit pupil diameter exceeds 5 mm, such as 8X42 and 7X50, it can be observed in a dim light environment (dusk, dawn, moonlit night, etc.). The telescope cannot be observed in a completely dark environment.
What is the difference between a Porro prism and a roof prism?
If there is no prism to transform the image, the image we see is an inverted image. The prisms commonly used in handheld telescopes are divided into Porro prisms and roof prisms. Porro prisms have good imaging effects and low prices, but they are large in size and weight. Roof prisms are small in size and weight, but they have the disadvantages of double aberration, phase difference, and inability to fully reflect. These defects need to be overcome by using high-precision prisms, phase films, and high-reflection films, resulting in a relatively expensive price for telescopes.The left side is the "Paulo prism" and the right side is the "roof prism"
What is the difference between BAK4 and BK7 ?
Porro prisms often use two kinds of lenses, BAK4 and BK7. The former has a high refractive index and can achieve total reflection of the entire field of view, while the latter has a low refractive index and the light at the edge of the field of view cannot be fully reflected. Therefore, the imaging effect at the center of the field of view is the same, while the image at the edge of the field of view will be darker with BK7 than with BAK4. However, the human eye's attention is mainly focused on the center of the field of view, so the imaging effect of the two prisms is not much different. The factory price of BAK4 prisms is more expensive than that of BK7, so low-end Porro prism telescopes often use BK7 prisms. Hold the telescope, keep your eyes 30 cm away from the eyepiece, and observe the shape of the exit pupil spot. If it is a bright circle, it means it is a BAK4 prism. If it is a circle with 4 dark corners, it is a roof prism. For roof prisms, it doesn't matter what material is used. Many roof prisms also claim to use BAK4 prisms, which are basically commercial propaganda, have no technical significance, and it is impossible to judge what material is used with the naked eye.
The left picture shows the BAK4 prism, and the right picture shows the BAK7 prism
What is the function of anti-reflection coating?
There are multiple sets of lenses inside a telescope, and each set of lenses has two reflective surfaces. If there is no anti-reflection film, at least 50% of the light will be consumed in the reflection on the lens surface, which will seriously reduce the brightness of the image, reduce the contrast, and make the image look foggy. Therefore, it is necessary to coat the lens surface with an anti-reflection film to reduce reflection. The most traditional anti-reflection film is a single-layer film, which reflects blue light, commonly known as a blue film. The anti-reflection effect of a multi-layer anti-reflection film is better, and the reflection is mostly green, commonly known as a green film. Based on this feature, many manufacturers intentionally manufacture low-cost single-layer green reflective films, commonly known as decorative films, which are harmful to imaging. Everyone must be vigilant. The color of the coating is not the key, the key is whether the reflected light is weak. The weaker it is, the lower the reflection and the better the anti-reflection effect.
What is the function of nitrogen waterproofing ?
Nitrogen-filled waterproof telescopes are filled with dry nitrogen. Moisture in the air cannot penetrate into the interior, and mold will not grow inside the lens. They can be maintained and used for a long time and are suitable for various outdoor activities.
Are military telescopes the best?
Absolutely not. Military binoculars are used in battlefield environments and mainly emphasize durability and high reliability. They do not require high optical quality and details. The so-called Type 62 military binoculars are not as effective as the Forester 8X30 standard version, which retails for 238 yuan. In the past, only the military was equipped with binoculars, and ordinary people could not afford them (you could only buy a Panda binoculars if you didn't eat or drink for half a year), so the myth of the good effect of military binoculars was created. In addition, with the development of optoelectronic technology, the role of binoculars in the army has continued to decline. If ordinary people do not have a love for military products and do not climb mountains and cross ridges every day, they should not buy military binoculars, which are extremely impractical.
