70-200mm lens-related knowledge.
We often use a stage photographic lens is 70-200mmf2. .8 Lens. . Talk about it below:. .
70-200 is the focal length of each strip is critical of the lens, the focal length of the segment is very popular, selling only to be treated as a standard 28-80 lens with a focal length of the period, the success is inextricably linked to the life or death. Moreover this lens development has been a long time, optical structure has a very mature, but in order to maximize the image quality of the lens of standards, and almost every family in the generous applied on the lens like the coke and low dispersion glass and more costly technology, constant aperture of doomed the product as a premium price of goods.
However, for the original, there is no doubt that they are a leading optical technology, in order to meet the demanding professional user satisfaction, and their products in both mechanical and optical levels to achieve the best for this camera optical products, they constitute the most critical is the lens glass lens. As we all know is a good shot mainly from the German Schott glass used in optical glass, it made the world's best optical products. .
But Japan's lens no matter how hard, there is still a gap, this is the power of the glass. Now for the original and Vice factory of such claim. In Japan, the lens works like Nikon, Canon, Pan Pacific Comox that has its own glass factory, the lenses of the formulation and production technology are highly confidential. In Vice factory, glass production is the highest level of tuli, ED glass and many well-known manufacturers use. But do not know why, Figure Korea itself is rarely used such high-end expensive materials, but it produces large diameter ED glass production, the top three in the world, like the single price of 300 mm in diameter in more than 70 thousand yen , huh, huh. Several of the world may not have such capacity. .
Then there is the ability to design. In optics, Japanese design of the most powerful no doubt is Canon's optical research, especially in recent years, Canon's pioneering work in optical very much, although it cannot be used with the Chase was founded the classic structure compared in regard to the application of the plant of true leading 5-10 years. In very important electronic optics Canon in many key technologies have decisive force of the patent right, just like the ultrasonic motor technology, beginning the factory limited to patent, spend a lot of time in an attempt to develop a competing technology. Results within less than 5 years including Nikon, Minolta AF cameras are able to provide these production plants have a comprehensive approach to the ultrasound. (Until now this trend is also constantly being shown). .
In Japan, there is a design and reverse design ability strong manufacturers — shima. This is a historical short professional lens factory, which is dependent on a design center. Their strengths lies in the ability to reverse the design is very strong, we should feel, no matter what the original launch of the new technologies, he is always the first to follow up. This is because the company's vulnerability management experience in the production of history and lack most of their lenses are not durable at an early stage or low-quality machine, this point than the Tamron, and Tokina's firm is really no choice; Although some improvement now, but "preconceptions," the impression is not able to reverse overnight, let alone the quality of this Sigma lens is still not processed, and N, C and other major companies to compete. .
The quality of the camera lies in low dispersion glass:.
Here have to emphasize the quality of low dispersion glass. Now the camera casually say how many blocks they used low-dispersion glass, but the manufacturers of low dispersion glass, there is a hierarchy among the points. .
First, the calcium fluoride glass, which is now nature's best low dispersion optical material, the main ingredient is calcium fluoride, this is a very high chemical stability of chemicals, acid and basic resistance, it is not very easy to dissolve in water. Because of this, there are very few natural crystallization, artificial Crystal is difficult, the biggest drawback is fragile and difficult to process, anti-vibration ability, the military is using magnesium fluoride to replace him to make infrared missile head covering. The camera lens on the use of calcium to make lens only Chase, Lycra and Canon. Other manufacturers are using a special mixture of low dispersion glass to achieve the purpose, in this regard is to minimize the problems caused by dispersion, the other aspect is to avoid the use of fluorite glass, so that the lens of the resistance capacity of harsh environment lower. .
Since the majority of manufacturers are using mixed glass, all plant products will inevitably bring differences. In a mixed glass, Canon's Super UD is the best, it is close to the optical properties of calcium, but also ordinary optical glass processing performance, and cost of production. However the application of the lens, but also to Canon's new product to see if that does not replace the active status. However, in contrast, the subsequent use of the product in the calcium may be less and less, instead, should be Super UD.
There is also a UD glass, Canon, and Nikon, Pentax, Olympus ED glass is used in the same type of thing, and this is so far the most mature production technology products. But the fact that several different optical properties or the whole, can only say that basically the same. The use of such glass in the product number, comparable with the same level can be considered as the same efficiency. .
For each pair of plants, their position and on the economic performance of value in this relative precious materials use some changes: first, use their powerful tuli raw materials production, developed a low-cost more, with lower dispersion of materials and a wide range of applications. However, such materials are also divided into several types: SD, SHD, etc..
Dragon is a clearly demonstrated that: their LD lens is not usually that low-dispersion lenses, only a low dispersion only. .
For shima, its lens also has several, and now also the large-scale use of to tuli and the Dragon, but slightly higher than them, and compare the original there is still a considerable gap. Shima is also ideal for low-dispersion glass the rough equivalent of ED glass, but as far as I know it's only in 180/.5 macro lens 3. use a tablet, but the price is high, lost and original products price-competitive advantages.
The difference between low dispersion glass, including the advantages and disadvantages of the lens can come from a structural point of view: low dispersion glass lens should be used in the most thick lenses. If not, and they rarely use low-dispersion lenses, such as a piece of that cover, like the Nikon 70-300ED, it can be said to deceive the consumer "gimmicks" behavior. .
Moreover, such as the calcium fluoride lenses generally cannot be glued with other lenses, only independent use, good low dispersion lens. For functional performance specification the same lens, lens, the more outstanding, this was mainly decreasing every single lens processing difficulty, more precisely all of aberration correction, but also on the factory coating level serious test.
Vacuum coating the lens:. .
From Japan's tests, now the world's production of various lens factory coating to Canon, Fuji, loc to three of the best that they can be more easily produced over 9 floors above layers. The rest of the Pan Pacific Comox SMC 7 layers, Chase T * 6 layers, Nikon MC, etc. are all very good.
Vice factory lens coating is the highest level of the Dragon, which has some of the more than original coating technology. The Ricoh such as manufacturers, including its acclaimed GR1 28 / 2. .8 Lens is only 3 to 5 layers only. We are more interested in the three Deputy factory lens, the Sigma is the worst. It's slightly more efficient membrane through other manufacturers, the most troublesome is its poor performance coating firm, has been lacking in areas of high humidity, high praise, such as Japan, Hong Kong, Chengdu and so on. This is why the lens of its useful life with the increase of very severe performance degradation is an important reason.In the secondary market, shima lens is often the most inexpensive and..
In the long focal length zoom lens variety, choose a lot, but for the real and practical application are far from imagination so much. For both the amateur or professional, this distance should be the choice of most of 70 (80) -200 (210), or 100-300. Now all the 75-300,28-200 the zoom lens, the image quality is still a big problem area, all belonging to a dog's head or something. .
Most stuck with bright or 70-200/2. .8 such a "big guy". This type of lens is now zoom lens inside the best lens. Aperture is big, the image quality is high, the most commonly used and a brief time level f/4 products belong to the bottom line is acceptable.
Common brand lens on the simple evaluation:. .
The following rashly to several product reviews, but one that will inevitably be too subjective, we must point flying bricks..
1. Let me talk about Nikon, Nikon 80-200 the focal length of the segment has introduced five generations of the earliest Ai-S is very rare, the price performance has been more mysterious, but according to the first generation of the AF of speculation should be the same. AF version of the generation of second-generation, optical structure of the same, just to improve the mechanical design problems have two different products, they were mainly hood position. The lens is generally very successful, although mechanical problems, the images live on the inverted Nikon known for many years.There was also a part of something unique, but slightly behind the current EF 80-200/2. .8L, was also known as affordable is a wanderer.
More perfect is really a third-generation Nikon AF80-200, this generation is not a reliable camera to the original ring structure into a double loop structure, joined the (false) within the focus, internal zoom design, which is generation of mature products, is now the Friends film called "Little Steel Gun (XGP)", which the lens in image quality over the previous two generations, also has been greatly improved, with the help of 3 ED glass, Nikon image on the full flavor, in the sales price also does not use a high pricing policy, moderate price has a great attraction, and even affect a lot of wavering between the NC Friends of the whereabouts of film, showing its extraordinary charm. .
The fly in the ointment is the XGP 200mm focal length large aperture imaging quality declines, as well as its large aperture scorch-imaging effects less, resulting in a lot of criticism.
Later, under the powerful offensive Canon, Nikon once again launched a new generation of AF-S 80-200, but you can see that this is a very mature product generation, despite the application of as many as five ED glass optical performance increase is very limited, many ways, less than previous models. Although the focus with a more rapid silent ultrasonic motor, but the volume and weight are extremely large, and though they appear in the hands of "extremely brilliant", but get up and feel able to balance the only F5. .
Seriously, this lens optical level are increasing, especially on the generation of up to 200 people has a focal length of performance gaps. However, it will be lost, in paragraph 80 of vist generation and current generation of imaging are increasingly going soft line, taste the "Nikon" less and less, making many N Home Home unhappy.
Therefore, the introduction of AF-S VR Nikkor70-200mmf2. .8 G, the view of the causes and the price of brand loyalty issue, N must be at home boss still has AF 80-200/2. .8 D ED New, and should not be rising with other home than the low. Because Nikon is the Nikon, but not others, unique. .
Then said the fate of Nikon's "the enemy" — the Canon.
After entering the era of Canon AF sudden force, and with excellent optical technology to seize the leadership of innovative technologies. Many lenses are the first to introduce professional fields, provide a very good L series lenses. However, the L is a pity that Canon L lens is the meaning of luxury, fire guns wildly stealing money;. .
Amateur level shots though many can give surprising, but there are a lot of people at the hut.
Canon's first 80-200/2. .8 L lens is a complete professional machine was introduced EOS-1, although the high price (at that time the most expensive, it really deserves the name L), but the image is very good, AF speed is to present standards see also the quick. Soon for the Canon professional photography in a vast world, a spit Nikon suppressed for years by foul smells. .
In ultrasonic motor technology is mature, Canon once again launched a powerful 70-200 lens, and later with anti-shake technology IS lens, the two lens no matter from that point of view, is excellent. To date, has not yet had its, well deserved the title of Emperor mirror. If you do not have innovative technical import, beyond this header is empty words.
No wonder so many years the factory, the lens prices change a little, but nowhere in the secondary market is difficult to find, this definitely see the level of users. .
However the two lens resolution than 80-200 years seems to be weak, but there is no sharp of a small increase, so the overall performance of a lot, especially in the end, reached 200mm focal length can be comparable to the level of focus.
Canon also did not give up on mid-priced camera market development, known as the "little white" of the 70-200/4L is such representatives, this lens is priced at about half white, for many cash-strapped Friends movie has a very strong attraction. .
Many people see this lens uses the calcium and Super UD lenses, think this lens will be better than the white, in fact they missed a very important issue: the lens resolution and maximum effective aperture, diameter, the greater the larger the light, the more information is collected, the appropriate resolution. Although some other optical, this rule is not disproportionate, but it is quite obvious.
Canon lens will be applied to set the "focus group after the" institutional turn became the "focus within the group type" (just move the middle lens group), and in the 70-200L zoom to achieve a high rate of and lightweight. According to Canon Lens Work description, within the group focusing type has the following advantages:. .
1. Because the only mobile lighter lens group, so the auto focus very quickly, manual focus is also very light and handy;.
2. . Lens length does not change because of focus;. .
3. Implementation of a lens system overall lightweight;.
4. . Filter box does not rotate;. .
5. When af af-looping will move forward or backward.
