The difference between multifocal lenses and ordinary lenses
There were many differences between multifocal lenses and ordinary lenses: 1. ** Number of focal points **: Multifocal lenses have multiple focal points, while ordinary glasses only have one focal point. 2. ** Adjusting Function **: Multifocal glasses can use different focal points when viewing distant objects, intermediate objects, and short-range objects, which can help improve the adjustment function of the eyes. When ordinary short-sighted glasses are used to view objects, there is only one focal point regardless of the distance, and it cannot be adjusted. 3. ** Target group **: The multifocal lenses provide clear vision from far to near for presbyopsia. Teenagers can use multifocal lenses to alleviate visual fatigue and slow down the speed of visual decline. The elderly can use them to help improve eye adjustment and avoid visual fatigue. Ordinary lenses do not have such special functions for different groups of people. 4. ** Price **: Multifocal glasses are made with high craftsmanship, and the price is usually higher than ordinary glasses.
The difference between bright moon lenses and ordinary aspheric lenses
Bright Moon lenses had ordinary aspheric lenses, but there were also other types of lenses. If the bright moon lens was compared with ordinary aspheric lenses, ordinary aspheric lenses had problems such as the definition getting worse as they went to the edge, only ensuring that the middle part of the lens was clear, and sometimes the field of vision was limited. Mingyue's PM lenses had a light transmission of 98.6%, which was better than other domestic brands and improved the visual experience significantly. However, Mingyue's 1.74 lenses were too expensive and not cost-effective for high myopes.
The difference between camera lenses
There were many ways to differentiate between camera lenses. The following are the differences in different aspects: ** I. By focal length ** 1. ** Fisheye lens ** - The focal length range is usually 7.5 - 13 mm. The angle of view was very large, and it could shoot special circular or extremely exaggerated effects. The depth of field was long, and it could make the proportion of the near, big, far, and small of the deep scene strong. The image had a strong sense of perspective, but the image distortion was large, especially at the edge of the image. When shooting at close range, the distortion was obvious. 2. ** Super wide-angle lens ** - The focal length was between 17 - 24 mm. It had the characteristics of a large angle of view and a large depth of field, which was beneficial for shooting a wide scene in a narrow environment. It could clearly show the subject with a large depth, but there was also the problem of large distortion at the edge of the image. 3. ** Wide-angle lens ** - 28 - 35mm focal length. Compared to the super wide-angle lens, the angle of view was slightly smaller and the depth of field was larger. It could be used for shooting a variety of scenes, but there might be some image distortion at the edge of the picture. 4. ** Standard Shot ** - The focal length is 45 - 58mm (usually 50mm). Its angle of view was similar to that of the human eye (about 50 degrees), and the image quality was relatively high. It was widely used in various types of photography and had strong adaptability. 5. ** Medium and long focal length lens ** - 80 - 135mm focal length. This focal length was more commonly used in portrait photography. It could use perspective distortion to produce special effects. 6. ** Long focal length lens ** - Like 200mm, 300mm, 500mm, etc. The depth of field was small, which was conducive to capturing the image of the combination of virtual and real; the angle of view was small, which could capture a large image of the scene from a long distance, suitable for shooting objects that were not easy to approach, and the perspective relationship was greatly compressed. The image distortion was small, and it performed well in portrait photography. 7. ** Ultra-long focal length lens ** - 1000mm focal length and above. It could be used to shoot objects from extremely far away. ** 2. Sorting by whether the focal length can be changed ** 1. ** Fixed focus lens ** - The focal length of a fixed-focus lens was fixed. At the same level of technology, the image quality of a fixed-focus lens was often better than a zoom lens. For example, an 85mm fixed-focus lens was used by many professional photographers for portrait photography. Its image quality was basically the ceiling of the image quality of various lenses. 2. ** Zooming lens ** - The focal length of the lens could be freely adjusted within a large range, such as a 24 - 105mm zoom lens. However, under the same quality and technical level, its image quality was worse than that of a fixed-focus lens. ** 3. By Aperture (Aperture)** 1. ** Large-caliber lens ** - The maximum relative aperture (maximum aperture) was F1.0, F1.2, F1.4, F1.7, F1.8, F2.0, F2.8, etc. A large aperture lens had the advantage of shooting in dimly lit environments, and it could obtain a shallow depth of field, making the background blur effect better. 2. ** Medium-caliber lens ** - The maximum aperture was F3.5, F4.5, F5.6, etc. 3. ** Small Aperture Shot ** - The maximum aperture was below F8. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Ordinary and good-looking cosmetic contact lenses
I recommend a few appraising novels. Treasure Eyes was an urban supernatural novel written by Ghost Deng Huo. The salesman relied on the treasure eyes transformed from the soul of a strange beast to explore treasures and appreciate the cultural accumulation of ancient and modern China and foreign countries. " She Has a pair of Golden Eyes " was an ancient romance novel based on the story of Fog City. It told the story of Qiao Anyi's life being disrupted by an imperial edict, her elder sister Mei Xue causing chaos in the capital, and the story of the Prince of Shu. It was heartwarming and cruel. " Pearl Light Mirror " was a modern romance novel about a short-eared cat. After the female protagonist was abandoned by a wealthy family, she relied on her superpower to appraise treasures and walked towards a wonderful life. It was considered good in the female version of the treasure appraisal novel. " Golden Pupils " was an eye-catching urban novel. Zhuang Rui, a pawn shop clerk, had his eyes mutated and entered the fields of antiques, stone gambling, and so on. This was the founder of the art of appraising treasures. It was a work that was eye-catching. It involved a wide range of knowledge and could increase one's knowledge while reading it. I recommend everyone to read it. "Luo Mingxia Love Letter" is equally exciting. Everyone is welcome to click and read it!
Lenses and Cameras
The lens was one of the core components of the optical imaging system. It was a key component of optical instruments such as cameras, video cameras, and telescopes. It was composed of lenses, mirrors, filter, and other optical components, which could change the direction of light transmission, focus light, filter light, etc. Its role was to convert the target object into an image through the optical imaging system and pass it to the receiver (such as camera sensor, human eye, etc.) for recording or observation. Cameras were also known as computer cameras, computer eyes, electronic eyes, and so on. They were a type of video input device. Just like human eyes, they could record and store the real environment they saw in the form of data. They had basic functions such as video recording and still image capture. After it collected the image (light signal) through the lens, the image was processed by the sensor circuit and control component in the camera and converted into a digital signal that the computer could recognize. Then, it was input into the computer through a parallel port or USB connection, and the image was restored by software. The main components of the camera are the lens, image sensor, pre-amplifier, ADC (automatic gain control), and A/D. It consists of a synchronous signal generator, a LCD driver, an image signal forming circuit, a D/A conversion circuit, and a power supply circuit. The optical image generated by the lens was projected onto the surface of the image sensor, and then converted into an electrical signal. After A/D (ADC) conversion, it became a digital image signal, which was then sent to the digital signal processing chip for processing. Then, it was transmitted to the computer through the USB interface for processing, and the image could be seen through the display. In the field of camera manufacturing, the airtightness of the lens was a vital indicator. It was directly related to the image quality and service life of the lens. There were technical difficulties in the airtightness test, such as the selection and precision requirements of the airtight instrument, the design of the lens tool and sealing tool, the training of the operator, the operating procedures, and the appearance protection. Different types of cameras had different features and functions. For example, Glory's hand-picked Xiao Pai smart camera Pro was equipped with three high-resolution lenses, supported cable network and dual-band Wifi, had a larger monitoring range, dual-screen monitoring, real-time tracking, 330-degree horizontal and 100-degree vertical adjustment, supported up to 20x hybrid optical zoom, had two types of fill light at night, supported multiple detection modes, and had a two-way voice call function. There was also a dual-lens camera that could rotate 360° without dead angles, and a fixed camera position to achieve remote alarm. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What's the difference between domestic micro-lenses?
There were many differences between domestic micro-lenses: ** 1. Price ** 1. ** Low-priced and affordable ** - Some of Yongnuo's lenses were more affordable, such as 35F2, 501.8, 851.8, etc., especially Yongnuo 501.8, which used to be sold for a few hundred yuan. It was a good choice for users with a small budget. - ttArtisan 56mm F1.8 was priced at 867 yuan, which was relatively cheap and guaranteed basic image quality. 2. ** Mid-priced model ** - The 33F1.2 Sniper Series was priced at 1599 yuan. - Some of Vizos 'lenses were in the middle of the price range. For example, the 85mm F1.8Z was priced at 2299 yuan, and the 24mm F1.8 was priced at 2499 yuan. 3. ** Higher Price Type ** - The Meike 851.4 full-frame lens was priced at around 2880 yuan. - The price of the Vizos 75mm 1.2 half-frame lens was 3500 yuan. ** 2. Focus Section ** 1. ** Standard focal length ** - Yongnuo had 35F2, 501.8, 851.8 and other lenses that covered the standard portrait focal length. - Vizos also had 161.8, 241.8, 351.8, 501.8, and 851.8 full-frame lenses that covered mainstream portrait focal lengths. The 231.4, 331.4, 561.4, and 131.4 fixed-focus lenses under the APS-C frame were equivalent to 20, 35, 50, and 85 focal lengths for the full-frame. - The Si Rui Sniper series had lenses that corresponded to the classic focal lengths of 35, 50, and 85. 2. ** Special focal length ** - The Si Rui Sniper series had a 23mm focal length lens, and its full aperture was very shocking. However, this focal length did not have ED lenses, but were all high-refraction lenses. ** 3. Performance ** 1. ** Dispersion Control ** - The Si Rui Sniper series still had room for improvement in controlling the dispersion, but the Meike 851.4 used an ED lens to effectively control the dispersion. - Some of Vizos 'lenses also had good dispersion control capabilities, such as some of its lenses equipped with ED dispersion lenses. 2. ** Automatic Focus Ability ** - Vizos was more successful in autofocus. It had introduced autofocus lenses with multiple portrait focal lengths, such as 161.8, 241.8, 351.8, 501.8, 851.8, etc. - Previously, there were 7 - 8 sub-factory lens brands of Nikon Z-mount, but none of them supported autofocus until Vizos launched the first sub-factory Z-mount lens that supported autofocus. 3. ** Image Quality ** - The 56mm F1.8 of the ttartisan could guarantee the basic picture quality. Some lenses such as 161.8 and 241.8 could also be used to shoot the Milky Way, which had better picture quality. - Judging from MTF, the Vizos Z-mount 24mm F1.8 image quality might not have high expectations. ** 4. Appearance and material ** 1. ** Material ** - Yongnuo's different lens models were made of different materials. For example, the 85mm lens barrel was made of a high molecular material, and the front end of the rubber focusing ring was made of a high molecular material. The 35mm lens barrel was made of an aluminum alloy material, and the 42.5mm lens was made of a high molecular material. 2. ** Exterior design ** - Different brands of lenses had different designs. For example, in terms of the process of the lens logo, the Yongnuo 85mm product information was marked with a gray layer on the lens barrel, while the 35mm lens used the anodisation process and the font was engraved with laser engraving. - There were also opinions that some domestic lenses still had room for improvement in terms of appearance design, such as the shape of the lens and the design of the LOGO. For example, Wei Zhuoshi was suggested to make the lens design more beautiful, and the logo could be re-designed. ** 5. Focus on the picture frame ** 1. ** Full-frame shot ** - Meike 851.4 was a full-frame lens. Yongnuo, Vizos, and other brands also launched full-frame lenses, such as Yongnuo's 35F2, 501.8, 851.8 (there were Sony E-ports and Nikon Z-ports, etc.), and Vizos '161.8, 241.8, 351.8, 501.8, 851.8, etc. 2. ** Half frame shot ** - The 56mm F1.8 of the ttArtisan was a half-frame lens, while the Vizos also had 231.4, 331.4, 561.4, and 131.4 fixed-focus lenses under the APS-C format. Yongnuo also had the 501.8 half-frame lenses with the Sony-mount. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Ordinary people can't wear Bright Moon lenses.
This statement was not accurate. The Bright Moon lenses were of good quality in all aspects, and there were many types of lenses to choose from. There were many customized products in the design of the lens base material, and the price was controlled within a certain range with a number of patents. The conventional lenses had a high cost-performance ratio. Judging from the four elements of lens evaluation: in terms of film layer, Tianshi A6 film has the advantages of easy cleaning and anti-oil; on the base material, the quality of KP resin is stable and safe; the KP super tough lens is suitable for frameless glasses and sports scenes; the light transmission rate, Abbe number and reduction degree of the PM series are high, and the overall comfort is good. The 1.71 index of refraction series is cost-effective for people with a temperature of 500 - 900 degrees. Although there were some situations such as the edge problems of 1.71PM lenses, the expensive unconventional lenses, and the dark color of anti-blue lenses, this did not mean that ordinary people could not wear them. It was still relatively friendly to regular customers with moderate budget.
The Theory of Photographic Lenses
There were many aspects to the theory of the camera lens: 1. ** Focus ** - Different focal lengths were suitable for different scenes and subjects. The focal length of a standard zoom lens generally starts from 24mm or 28mm, covering 70mm to 120mm, such as 24 - 105mm, 24 - 70mm, 28 - 70mm, etc. It has a wide range of shooting areas, suitable for portraits, scenery, humanities, cities and many other subjects. It is a common lens type for beginners, and it is also one of the most commonly used lens types for experienced photographers. - The focal length of the telephoto zoom lens was above 200mm, such as 70 - 200mm f/2.8, 70 - 200mm f/4, suitable for shooting portraits, flowers, plants, and street humanities. If you want to shoot birds, lotuses, and long-distance scenery, you may need a lens with a focal length of more than 300mm, such as 70 - 300, 100 - 400, etc. The advantage of a telephoto lens was that it could shoot without disturbing the subject, and it could bring a good blurring effect. - Fixed focus lenses had fixed focal lengths, such as 28mm, 35mm, 50mm, 85mm, etc. They had good image quality and a large aperture. They were relatively friendly to portrait subjects, but they could not be zoomed. There were certain requirements for the photographer's operation level. 2. ** Aperture ** - The aperture size of the lens affected the amount of light entering and the blurring effect. For example, Canon's EF24 - 105mm 1: 4L IS II USM lens had a maximum aperture of F4 and was constant, while Nikon's NikKOR 70 - 200mm 1: 2.8G II ED lens had a maximum aperture of F2.8. The maximum aperture of a non-constant aperture lens would change according to the focal length. For example, 18 - 135mm 1:3.5 - 5.6, the maximum aperture at 18mm at the wide-angle end was F3.5, and the maximum aperture at 135mm at the telephoto end was F5.6. 3. ** Regarding the lens mount ** - Different brands of cameras had different lens mount types. Canon's EF-mount was used for full-frame and APS-C format cameras, while the EF-S mount could only be used for APS-C format cameras. There was also the TS-E shift-axis lens mount. Nikon had AF-S lenses that supported ultrasonic motor autofocus, and its DV represented the name of a non-full-frame digital single-lens reflex camera, while its Felix represented the name of a full-frame digital single-lens reflex camera format. 4. ** Special Function ** - Some lenses supported anti-shake function. The "IS" in Canon's lenses indicated that it supported image stabilization, while the "VR" in Nikon's lenses indicated anti-shake. - There were also some lenses that used special lenses to improve the image quality. For example, the Nikon 70 - 200mm f/2.8E FO LED VR lens used ultra-low dispersion lenses (ED), which had excellent image reproduction capabilities. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
There are several kinds of lenses
There were C ports, CS ports, F ports, M72 ports, M95 ports, and so on. In addition, different camera manufacturers also had their own lens mounts, such as Canon's " EP," Nikon's " F," Pentax's " K," Sonny's " E," Pantheon's " LUMIX," Fuji's " X," and so on. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The parameters of Zeiss lenses
The following are the common parameters of Zeiss lenses: ###1. Focus 1. ** Perspective Relationship ** - The focal length determined the angle of view of the lens. For example, a focal length of 50mm (such as a Zeiss Touit 2.8/50 lens) provides a medium viewing angle. In portrait photography, this focal length was suitable for close-up shots, which could better capture the expression and details of the person. In landscape photography, although it was not the best choice, it could also take a unique photo. - Different focal lengths would produce different images when shooting the same object. A shorter focal length (wide-angle lens) could show a wider scene, while a longer focal length (telephoto lens) could zoom in on distant objects, highlight the subject and compress the sense of space. ###2. Aperture 1. ** Light Control ** - The aperture size (such as the f/2.8 in the Zeiss Touit 2.8/50 lens) directly affected the amount of light entering. A large aperture (with a small numerical value) had an obvious advantage in a low-light environment. It allowed more light to enter the camera, allowing it to take bright and clear photos. - The aperture was also related to the depth of field. A large aperture could create a shallow depth of field effect, blurring the background and thus accentuating the subject, adding an artistic atmosphere to the work. ###3. Optic performance related parameters 1. **MTF (Modulated Transfer Function)** - The MTF chart could reflect the contrast and resolution of the lens. By looking at the MTF chart, you can roughly understand whether the lens is a high-contrast lens or a high-resolution lens, which helps to evaluate the image quality of the lens before buying it. 2. ** Film coating technology ** - For example, the advanced coating technology used by the Zeiss Touit series lens was used to effectively reduce reflection and glare, ensuring the clarity and color reproduction of the picture. A good coating could improve the light transmission rate, reduce the loss of the image caused by light reflection, make the color of the photo more realistic and bright, and reduce the bad phenomena such as facula in the picture. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
About 30,000 Sonny lenses
Here are some of the lenses that are priced around 30,000 yuan or close to that: - The price of the lens was about 12400 yuan. - The price of a 135mm F1.8 GM lens was about 13399 yuan. There was also a Carl Zeiss Batis 135mm f/2.8 APO Sonnar PE lens, which cost about 13329 yuan. However, it should be noted that the actual price of the lens may fluctuate due to factors such as purchase channels and promotions. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>