Choosing the index of the camera lens
When choosing a camera lens, there were several factors to consider: ** 1. In terms of optical quality ** 1. ** Sharpness ** - Sharpness was the ability of the lens to reproduce details on the focal plane, which was the clarity of the edges and texture of the object in the image. High sharpness allowed the image to be clearer and finer, making it easier for the viewer to see the subtle differences. Excellent lenses had first-class optical design, materials, and lens grinding standards. They had good sharpness within the focal range. Fixed focus lenses, especially top-notch fixed focus lenses, had better sharpness. However, the sharpness of macro lenses was very outstanding among all lenses. 2. ** Distortion ** - The lens distortion was the distortion of the straight line in the image after the image was formed. It was common in wide-angle and zoom lenses, but almost all lenses had it more or less. Whether the lens had obvious distortion was an important indicator to measure its quality. 3. ** Dispersion (Color Deviation)** - When light passed through the lens, the refraction index of different colors of light was different. They could not converge perfectly at the same point on the imaging plane, and color stripes would appear at the edge of the high-contrast area of the image, such as "purple edge" or "green edge". Therefore, it was necessary to consider whether the lens was prone to this situation in high-contrast scenes. 4. ** Dazzling lights and ghostly shadows ** - This was directly related to the quality of the lens coating. A well-coated lens was not easy to produce glare or ghostly shadows under strong light. 5. ** Dark corner ** - It mainly depended on whether the lens had obvious dark areas under the large aperture. It was even more important to pay attention when using it on a full-frame body. 6. ** Fade out of focus ** - The beauty of the void-out was an important indicator. A good lens would take a photo where the out-of-focus part of the scene was evenly spread, the color gradually changing naturally and evenly, and the transition between in-focus and out-of-focus was natural. Some high-end lenses such as Canon EF200mmf/2L IS USM and Nikon AF-S 200mmf/2G ED VR II had outstanding out-of-focus imaging effects. 7. ** Image resolution ** - It refers to the ability of the lens to reproduce the subtle structure clearly. The higher the resolution, the stronger the ability to show the subtle differences in the image. It is more meaningful for digital cameras with higher frame factor. It could be measured by taking a black-and-white fringe pattern with a high-resolution photographic medium and analyzing it. 8. **MTF Value (Modality Transfer Function)** - This was a comprehensive evaluation of the sharpness, contrast, and resolution of the lens. ** 2. The material of the lens ** 1. [Durability] - Metal was usually stronger and more durable than plastic, but it was heavier, more expensive, and consumed more power when auto-focusing. In addition to the material itself, it also depended on the overall workmanship of the lens, including whether the vibration of the zoom ring and the focus ring was appropriate, whether the operation was smooth, and whether it was waterproof and dust-proof. This was very important for outdoor shooting. ** 3. In terms of autofocus performance ** 1. ** Focus Speed ** - The focusing speed of the lens under different lighting conditions was an important consideration. 2. ** Focus accuracy ** - Pay attention to whether there is a problem with the front and back focus (the focus "bellows" problem). 3. ** Focus noise ** - In video shooting, silent focus was especially important, so whether there was obvious noise when the lens was focused also needed to be considered. ** 4. Other aspects ** 1. ** Aperture size ** - The size of the aperture affected the amount of light entering and the depth of field effect. For example, the aperture value was marked with the letter f. The smaller the f, the more blurred the background of the subject and the lighter the depth of field. For a fixed-focus lens, a larger aperture could be achieved at a lower manufacturing cost. 2. ** Is it a constant aperture (for zooming lenses)** - A constant aperture lens could use its nominal maximum aperture at all focal lengths. 3. ** Focus Type (Fixed or Zoomed)** - The optical design and mechanical structure of the fixed-focus lens were simple, which could achieve higher image quality, larger aperture, and lighter weight at a lower cost. The zoom lens was more flexible in focal length adjustment. For example, the 85mm fixed-focus lens was considered by many professional photographers to be the king of portrait photography. It had advantages in terms of shooting angle, shooting distance, image quality, etc., but it also had shortcomings such as a fixed angle of view. Read more exciting novels for free
What is the lens of the camera lens?
Based on context alone The lens of the camera lens was made up of many different types of lenses. This included a concave lens, which had a thick middle and thin edge structure. It had a converging effect on light, which helped to focus the light on the imaging plane, making the image clear. There were also concave lenses, which were thin in the middle and thick at the edges. They had a diffusing effect on light and were often used to correct aberrations. In addition, there were also aspheric lenses. These lenses were not the traditional spherical shape. They could better correct aberrations, improve image quality, and reduce image distortion and blurring. They were widely used in modern camera lenses. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The camera lens changed to a projection lens
Some data showed that the telephoto projection could be used to change the camera lens into a projection lens, and a size image could be projected at a distance of 1.5 meters. He could also use a flashlight as the film's back light and a Nikon lens as the projection lens to make a simple projector and project the reverse film on the wall. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The camera lens is expensive
In the field of photography, expensive lenses had their value. Generally speaking, more expensive lenses had higher performance in terms of optical quality, workmanship, and performance. For example, in the field of medium and long focal length lenses, Canon's RF70 - 200mm f/2.8L IS USM was priced at 16999 yuan, and the Sony70 - 200mm F2.8GM OSS II was priced at 18999 yuan. These lenses were expensive, but they could provide better imaging results, excellent focusing performance, and good durability on their respective cameras. However, with the changes in the photography market, the relationship between price and value did not completely follow the traditional principle of "you get what you pay". In the micro-monocle era, although some high-end lenses had improvements such as quieter focusing, better design, and improved electronic functions, compared to similar lenses in the DSLR era, users felt less about the improvement in optical quality, but the price generally rose. Some of the affordable entry-level lenses, such as the 50mm f1.8 lens, were no longer as affordable as before. Branded lenses of this size were even hyped up to three times the release price. 24 - 105mm f4 or similar lenses were nearly twice as expensive in the micro-single era as in the single-lens reflex era. Although the optical quality had improved, there was no particularly huge breakthrough. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The lens and camera interface
The lens and camera interface was a component used to connect the lens and the camera. Suzhou Ouka optical instrument factory specialized in the production and development of a camera interface, this interface can be connected to different brands and models of lenses, so that the camera can be used normally. There are many types of industrial camera cable ports: - **USB port **: It is a commonly used port for digital cameras. It can directly output digital image signals. USB was the full name of Universal serial bus. The interface was 4-pin, including 2 power cables and 2 signal cables. There were different versions of USB. The early USB2.0 interface was convenient and widely used, but the transmission rate was slow (480Mbit/s), the communication distance was short (5m), and the band width was mostly used for image transmission (80%). The transmission required the CPU to participate in management and consumed a lot of resources, and the interface was unstable. USB3.0 added two sets of data lines on the basis of USB2.0, which were backward compatible. The transmission speed was increased to 4.8Gbit/s, and the communication distance was extended to 10m. However, the transmission distance was still relatively short. USB interface cameras were easy to use and had a wide range of ports. They were widely used in microscopes, scientific research experiments, portable equipment, and other industries. At present, USB Type Micro-B ports were the mainstream on industrial interface cameras. In the future, USB Type C ports might be popularized. - ** IMEE1394 (Firewire Interface)**: It is a high-speed serial bus. It supports hot swapping, real-time data transmission, and uses a bus structure. It is widely used in the industrial field. It has good protocol and coding methods, and the transmission speed is stable. The 1394a's maximum transmission speed was 400mps, and the 1394b's maximum transmission speed was 800mps (3.2mps was relatively rare). Its interface was divided into 4-core and 6-core. The 4-core contained two pairs of data cables, and the 6-core had a set of power cables in addition to the data cable. This interface did not require a controller and could be used for peer-to-peer transmission. The 1394a's maximum transmission distance was 4.5 meters, and the 1394b's transmission distance was usually 10 meters (100 meters, 100 Mbit/s, when the data rate was reduced). However, the interface's penetration rate was low and it had been slowly eliminated by the market. - **Camerlink interface **: A digital image signal communication interface protocol introduced by the Aia Association. It is a serial communication protocol that uses the LVVS interface standard. It was developed from the Channel Link technology, adding the transmission control signal and defined the relevant transmission standards. The protocol used the MDR - 26-pin connection or the SAR- 26-pin connection, which had high speed (up to 6400Mbps), strong anti-interference ability, and low power consumption. However, it required a separate CameraLink interface, which was not portable, expensive, and rarely used in practical applications. - ** Gige Giga-bit ether interface **: created and promoted by Aia. It is a camera interface standard developed based on the Giga-bit ether communication protocol. It is suitable for industrial imaging applications. It can transmit uncompressed video signals over the network and can use low-cost cables to transmit images over long distances. In addition, in the field of machine vision, other data transmission ports were also developed: - **CoaXPress (CXP) interface **: launched in 2008, supports high-speed imaging applications, uses 75 Omega coax cable, supports data transmission speed of up to 6.25Gbit/s per channel, and can increase the transmission rate of multiple channels. Each cable can provide up to 13W of power. It requires the "device" and "host" to support the GenICam camera programming interface. However, the cost of installing multi-channel cable components and frame clips on a single-channel coax cable increases rapidly. - **CameraLink interface **: In 2000, it was launched by Aia Association and gradually upgraded.（2.04Gbit/s）、Medium (5.44Gbit/s) and Deca/Extended (6.8Gbit/s). Base uses an ADC- 26 pin, medium/full requires a second cable to double the capacity, Deca/Extended can transmit up to 6.8Gbit/s data, and like the CXP interface, it requires an image acquisition card that is compatible with the CameralLink power supply (PoQL) standard for power supply. It lacks error correction or resend functions. The cable setup was expensive and troublesome. - **GigE Vision standard interface **: It is managed by the Aia Association and allows the use of existing low-cost ether cables, connections, switches, and other components. Copper cables can transmit image data up to 100 meters away, and more data can be transmitted through the switch and optical fiber adapters. It has the potential to create different network topologies. Each camera can be placed on the network independently through an IP address. It can be viewed, controlled, and monitored from any PC on the network. However, the maximum 115mb/s has limitations for certain applications. However, NBUSE-T technology could increase the band width within its framework. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Choice of camera lens
There were many factors to consider when choosing a camera lens. If it was shooting scenery, from a novice's point of view, although the wide-angle lens had a large scope and could shoot an imposing manner, there were drawbacks such as small changes in the image and difficult to grasp the perspective relationship. In contrast, the telephoto lens might play a greater role in scenery shooting, and the usage rate was higher. It could also take into account topics such as skits and portraits. The choice of fixed-focus and zoom lenses depended on the user's needs and the subject. The fixed-focus lens had better image quality and was suitable for portraits with high image quality requirements, which could produce better blurring effects. The zoom lens was easy to use and was suitable for traveling, street sweeping, and other scenes that required flexible shooting of various subjects. Tianya Mirror was suitable for people who pursued lightness and practicality. It had the characteristics of light weight, wide focal length coverage (from wide-angle to telephoto), and high playability. For example, Tenglong 50 - 400mm, Nikon Z24 - 200mm, Tenglong 50 - 300mm were all good Tianya Mirrors. For portrait photography, the commonly used focal lengths were 35mm, 50mm, 85mm, and 135mm. From a practical point of view, 50mm and 85mm could be chosen first. The 50mm lens could handle both indoor and outdoor shooting. 85mm was the golden focal length for shooting half-body and close-ups. 35mm was suitable for environmental portraits, and 135mm was suitable for close-ups of people. It could separate people from the background very well. In terms of movie lenses, the most important feature was the focus effect. After focusing, the focus would not change during the zooming process. This feature was suitable for live broadcasts and other scenes to avoid out of focus. In addition, lenses with different mounts (such as the EF-mount, the PL mount, the Sony-E mount, etc.) had different prices, performance, and applicable models. It was also necessary to choose a lens based on the actual camera model and other factors. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Foreground of the camera lens
In photography, the front of the camera was an important element in the composition of the picture. A lens with different focal lengths would have different effects on the background. For wide-angle lenses (such as 16 - 35mm focal length or a wider 17 - 24mm ultra-wide-angle lens), it had a larger depth of field and angle of view. This allowed the proportion of the background in the picture to be larger, and it could present an exaggerated perspective effect. It was beneficial to clearly present the subject with a large depth on the picture, and it could also shoot a wider scene in a narrow environment. For example, when shooting the interior of a building, you could use objects such as pillars close to the camera as the background, and at the same time show the distant space, enhancing the sense of space and depth of the picture. However, it should be noted that the image distortion is large, especially at the edge of the picture. When shooting at close range, you should pay attention to the distortion problem. Standard lens (focal length 24 - 70mm or 45 - 58mm, usually 50mm), its angle of view and imaging effect is close to what the human eye sees. When dealing with the background, the effect was more natural, and there was no strong perspective distortion like the wide-angle lens. It was often used for shooting a variety of subjects. The proportion of the background and the background was relatively balanced, and the image quality was relatively high. Telephoto lenses (such as lenses with a focal length of 70 - 200mm and above) had a small angle of view and a small depth of field. When the background was included in the picture, the telephoto lens could compress the space, reducing the distance between the background and the background. The ratio of the near and far was reduced, and the front and back scenes on the picture appeared very compact. This kind of lens was suitable for emphasizing the connection between the background and the background, or for creating a special atmosphere. For example, in portrait photography, the shallow depth of field of the telephoto lens was used to blur the background and highlight the main character. In photography, the reasonable use of the camera's perspective can increase the layering of the picture, guide the audience's line of sight, create an atmosphere, and convey a specific theme or emotion. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The camera lens changed
Here are some ways to change the scene: 1. ** inertia transition **: Use the inertia of people's thinking and visual inertia to achieve a natural transition between shots. For example, the photographer uses the process of the model crossing the stabiliser to achieve a natural transition between different scenes. 2. ** Seamless Diagonal Connection **: First, shoot a scene where the character walks sideways. Then, shoot a scene where the character stands at the three-point line and walks toward the person. When editing, he imported the video, turned off the original sound, clicked on the video bar, and changed the speed of each video to about 0.5. He clicked on one of the video bars to cut the picture-in-picture, pressed the video bar and dragged it to the position where he needed to start the transition, clicked on the mask, selected the linear mask, rotated the template line 30 degrees with two fingers and moved it to the upper right corner (or upper left corner), pulled the appropriate feathering to make the picture more integrated, added a key frame at the beginning, and then moved the mask line to the lower left corner (or lower right corner) at the position where the transition needed to end. He added music, adjusted the ending of the video to align with the music, and then imported it. 3. ** Up-and-down transition **: The photographer gradually moved the camera closer to the character (using the push-pull lens). When the camera was close to the object (such as a sunflower), the camera could be swung along with the upward movement of the object. When shooting, the stable shooting style of the iSteadyX could be set to the extreme speed style. The transition points included the speed of the camera swing should not be too slow (or accelerated later), and the camera should follow the hand swing. 4. ** Left and right swing transition **: The principle is similar to the up and down swing transition. When the previous shot ends with an upward swing, it is best to start the next scene with an upward swing. The key point of the transition is to use the same action as the previous shot as the opening to continue the next scene. The speed of the swing cannot be too slow (or faster in the later stages), and the camera moves in sync with the hand swing. 5. ** Cover transition **: The camera is temporarily covered by a specific image, and the transition is achieved through this specific image. For example, if the scene in the previous second was blocked by a drink that was gradually approaching, the next shot could naturally show the scene to another scene through this block. It could also be combined with the Inception function of iSteadyX, that is, while using Inception to shoot a rotating image, the camera was gradually moved closer to the cup to make the image more vivid and smooth. The key point was to push and pull the lens closer to an object to block the transition, and then add Inception to make the image rotate. 6. ** Overlay Occlusion transition **: The previous scene used a drink to block the transition, and the next scene used another object (such as a hand) to block the transition. Using different objects to overlap the transition, the blocking method could no longer be singular. With the help of the hand pulling action, the scene gradually zoomed out, thus explaining the environment of the character. This could also be combined with the Inception function of iSteadyX. While using Inception to shoot the rotating scene, gradually move the hand away to make the scene more vivid and smooth. The key points included pushing and pulling the mirror away from/close to an object, plus Inception to rotate the image, and using different objects to cover it. 7. ** Similar Relational Item Transfer **: Using the relationship between similar objects as the transfer medium, the camera zooms in or zooms out to complete the change of the scene, characters, environment, and other elements. 8. ** Shape-shifting, Direction-shifting, Similar Motion-shifting **: These are also transition methods, but the operation method is not mentioned in detail. 9. ** Skill-less transition-two-level shot transition **: There are requirements for the difference between the scenes of the two scenes. The scenes of the shots can be divided into far, full, middle, close, and special. The long distance and close-up are the two extremes. The huge contrast between the scenes before and after the scenes, the changes in movement, and so on, can be used to form an obvious paragraph interval, which is suitable for the transition of large segments. 10. ** No Skill Transfer-Empty Shot Transfer **: When the purpose is to portray the emotions and mentality of the character, there is an obvious interval effect when there are only scenes without characters. It can increase the appeal of the work. It is mostly used to switch to a new city in the film and television plot, and to switch between the scenes in the natural environment (such as between the sky and the desert, between the jungle and the sea). 11. ** Skill-less transition-similar transition **: Use similar shots of objects or characters in two scenes to combine together. In addition to similar conditions in terms of shape, position, location, etc., it is best to satisfy the internal connection between the two scenes. It can be used in creative advertisements, short films, vlog forms, etc. Do not force yourself to find similarities. 12. ** The transition method of the technique-Fade In and Fade Out **: Change the video's clarity. Fade In is the beginning of the second shot, and Fade Out is the end of the first shot. There are three ways to use it. Fade In is used at the beginning of the first shot; Fade In and Fade Out is used to skip the middle time, which represents the transition of two scenes in the movie or the skipping of time; Fade Out is used. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Pictures of the camera lens
The reference 3 mentioned that there was a complete picture of the lens and focal length (collection), which included the core data of the camera, the brand lens and focal length, and the frame. However, it did not mention how to obtain these pictures, so it could not provide more information about the photo lens. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Canon camera lens
In Canon lenses, the half-frame lens was a golden circle 17mm-55mm F2.8 lens. There are many red circle lenses in the common lens of the full frame, such as 24mm-70mm F4, 24mm-105mm F2.8, 24mm-105mm F4, 70mm-200mm F4, 100mm-400mm (golden circle), 70mm-300mm f.(The specific parameters after the aperture are not specified), etc. Among them, 70 - 200mm F2.8 is also regarded as the lens of the Emperor of Mirrors. These lenses had excellent performance in their respective focal lengths and application scenarios, such as excellent image quality and focal length adaptability. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is a camera lens?
The camera lens was an important part of the camera and had many functions and characteristics. In terms of focal length, there were lenses with different focal length ranges, such as fisheye lenses (7.5 - 13mm), ultra-wide-angle lenses (17 - 24mm), wide-angle lenses (28 - 35mm), standard lenses (45 - 58mm, generally 50mm), medium-long focal length lenses (80 - 135mm), long focal length lenses (200mm, 300mm, 500mm), ultra-long focal length lenses (1000mm and above), etc. According to whether it could be zoomed, it could be divided into fixed-focus lens and zoom lens. The zoom lens could change the focal distance and freely adjust the focal length within a large range, but the image quality was worse than the fixed-focus lens under the same technical level. The aperture of the lens referred to the largest relative aperture, which was the largest aperture. There were large apertures (such as F1.0, F1.2, etc.), medium apertures (such as F3.5, F4.5, etc.), and small apertures (below F8). Different types of lenses had different characteristics in terms of angle of view, depth of field, image quality, shooting range, etc. For example, wide-angle lens had a large depth of field and angle of view, which was conducive to shooting a wide scene in a narrow environment, but the image distortion difference was large. Telephoto lens had a small depth of field and angle of view, which could capture a large image of the scene from a long distance with a small image distortion difference. The compression of perspective relationship shortened the depth of the picture, which was conducive to capturing the image of the combination of virtual and real. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>