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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 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>

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.

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 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 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>

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>

Within the budget range of 20,000 to 30,000, the following are some DSLR lenses to choose from: - Canon: - Canon's original 24 - 70mm/2.8L red circle lens, paired with Canon cameras (such as the 5DmarkII body), was a good choice. - The RF24 - 105F2.8 lens had the first features of many Canon lens systems, such as aperture ring, anti-shake gear switching, internal zoom, etc. It could meet the needs of shooting from 24 wide-angle focal length to 105 medium-long focal length. - Nikon: Nikon has a 24 - 120f/4 lens. Apart from the small aperture, the overall performance is good and suitable for home use. There are also sub-factory lenses such as 35 - 150f2 - 2.8 from Tenglong. - "Sony: The lens selection is relatively rich. In addition to conventional focal length lenses such as 35mm, 85mm, 24 - 70mm, 70 - 200mm, 24 - 105mm, there are sub-factory lenses such as the Tenglong 27 - 75f/2.8. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

Here is some information about lenses for Canon and Soni cameras: - Canon would launch a new macro lens in the first half of 2025, with a focal length of more than 100mm. The price was expected to be higher than the existing Canon RF100mm F2.8L MCROIS USM lens. - Canon RF70 - 200mm f/2.8L IS USM medium telephoto lens (Canon RF-mount). - A few hundred yuan Canon ESF50F1.8 fixed-focus lens was suitable for beginners. - SonyFE24 - 70mm f/2.8GM II (SEL2470GM2) standard lens (FE-mount). - Multiple sources have confirmed that by the end of November, the company will release the 24 - 70mm F2.0 GM lens, as well as upgraded models of the A1 and A7M4. - For beginners, the 50F1.8 lens of the Soni e-port was suitable for shooting with the ZVE10 second-generation lens. The large aperture was easy to shoot and light. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>