How to choose the focus of the lens
There were two main methods of lens selection: autofocus (AFF) and manual focus (MT). ##1. Automatic Focus (AF.) 1. ** Single Point Focus **: This is a common autofocus mode. The camera automatically detected and locked onto this point to focus. It was suitable for situations where one wanted to accurately focus on a subject. 2. ** Continuous Focus (AI Servo / Continuous AF.)**: It is suitable for shooting fast-moving subjects, such as athletes or running animals. The camera would continuously focus on the moving subject to ensure that the subject remained clear during the movement. 3. ** Area autofocus **: - There were also square, vertical, and horizontal focusing methods. When shooting, the selection can be made according to the characteristics of the captured scene. For example, when shooting a scene with a regular shape distribution, the corresponding area focusing method can be selected according to the shape layout of the scene to better focus on the main body in the picture. - Some cameras had different types of AFs depending on the characteristics of the subject. For example, Canon's Eos70D had three types: ONE SHOT (Single Flash AFs), AI Focus (Artificial Intelligence Focus AFs), and AI Servo (Artificial Intelligence Servo AFs). - ONE SHOT: Once the shutter button is pressed halfway, the camera will start autofocus. Once it is in focus, the focus position will not change. It is suitable for shooting still objects. - AI Servo (Artificial Intelligence Servo-auto Drive): When the shutter button is half-pressed, the focus will move with the object even if the object is moving. ##2. Manual Focus (MV) 1. ** Operation method **: Switch the focus mode of the lens to MV, then look at the viewfinder or LCD monitor while rolling the focus ring of the lens to focus. 2. ** Usage **: - In some special shooting scenes, manual focus was more advantageous. For example, in macro photography and night photography, autofocus might not be able to accurately focus on the desired subject. Manual focus allowed the photographer to accurately adjust the focus position according to his own creative intentions. - In complex environments with low contrast, low light, or interference, autofocus may have difficulty finding the focus or focus errors. Manual focus can rely on the photographer's experience and skills to complete the focus. - If you want to create a special artistic effect, such as deliberately focusing on an element in the background to create a unique layering and artistic conception, you can use manual focus. In actual shooting, such as shooting a large scene (wide field of view, large depth), you can use a small aperture with "hyperfocal focus" to make most of the picture as clear as possible. When operating, you can first twist the focusing ring to the "infinite distance" position, then find the clear scene closest to the lens (hyperfocal point) and focus on this point. When taking portraits, if the proportion of the face in the picture was not large, consider focusing on the face first; when taking headshots and close-ups of the face, focus on the eyes. Focus on still objects when shooting long exposure shots such as flowing water and traffic trails. Read more exciting novels for free
How to choose the focal length of the lens of the fixed-focus lens
The focal length of a fixed-focus lens depended on factors such as shooting requirements, style, and budget. The following are the characteristics of different focal length fixed-focus lenses for reference: ** 1. 35mm focal length (micro-wide angle lens)** 1. ** Strengths ** - The angle of view was closer to the eyes, and it could produce a natural and layered portrait effect. When shooting a portrait, some environmental elements could be incorporated. - It was suitable for shooting indoors, street scenes, and traveling scenes. 2. ** Flaws ** - The need for a closer shooting distance may cause distortion or unnatural stretching of the character, such as when shooting an upright half body and a big head. - It required a high level of composition ability, because the picture contained a lot of information, and it was easy to have a messy or boring effect. - A high aperture value was required. Due to the large depth of field of the wide-angle lens, it was more difficult to capture the effect of shallow depth of field and background blurring. ** 2. 50mm focal length (standard lens)** 1. ** Strengths ** - The angle of view was close to the focal range of the human eye. It could shoot a balanced and prominent portrait effect. It could adapt to portraits, animals, still life, streets, cities, and many other scenes. - It was the first choice for many people to get started with fixed-focus lenses. It was relatively cheap, had a large aperture, high quality, good sharpness, and was relatively easy to master. 2. ** Flaws ** - The angle of view was flat. The close-up shot was not as good as the 85mm lens, and the angle of view impact was not as good as the 35mm lens. It was difficult to shoot with characteristics and creativity. - It was more difficult to focus, especially when the aperture was fully open. It was easy to make mistakes that were out of focus or out of focus. - The limited space in the room made it difficult to shoot the whole body or half of the body. ** 3. 85mm focal length (medium telephoto lens)** 1. ** Strengths ** - The angle of view was relatively narrow. It could highlight the main body of the character, greatly blur the background, and create the effect of separating the person and the scene. It was suitable for shooting full-body portraits, half-body portraits above the waist, close-up scenes, and so on. - It was a very classic focal length in portrait photography. It had the reputation of a beauty mirror and a portrait mirror emperor. It also had a little decorative effect. - The image quality was basically the ceiling of all the cameras. 2. ** Flaws ** - Its usage was very limited. It was almost useless indoors, and it also needed to maintain a certain shooting distance outdoors. - The price and weight were both high, especially for large aperture focal lenses, because more glass components and more complicated structures were needed to achieve a large aperture and long focal length. - The camera and technical requirements were relatively high. It required a certain degree of anti-shake function and high photography ability to shoot better works. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Focus the lens
Theoretically speaking, lens focusing was to change the image distance (v), which was the distance between the lens 'optical center and the film plane. For a microscope, it was the process of adjusting the distance between the objective lens and the object to obtain a clear image of the object. In a camera, focusing (focusing, focusing) was to adjust the focus of the lens to the exact position of the subject to take a clear picture. Whether the subject was still or moving, accurate focusing could ensure that the subject was clear. Except for some low-end camera lenses that could not change the image distance because they did not have a focusing mechanism, other lenses, whether fixed-focus or zooming lenses, could change the image distance to get a clear image. In lens imaging, the image has the clearest position on the screen (camera film or sensor). Countless such points form the focal plane. Focusing is to change the front and back position of the focal point to satisfy the imaging formula 1/u + 1/v = 1/f (u is the object distance, v is the image distance, and f is the focal length), so as to form a clear image on the film. When shooting distant objects, the object distance was far greater than the focal length, and the image distance was close to the focal length and almost unchanged. At this time, the concept of "depth of field" was also involved to ensure the imaging effect. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The focus of the lens is horizontal
If the lens was focused on a horizontal line, it might involve knowledge about the linear focus point. The linear focus point could be divided into horizontal and vertical. When using the horizontal linear focus point, if there was a line on the focus subject that intersected with the horizontal linear focus point, the focus could be automatically focused. However, if the object being shot was a horizontal line that was parallel to the horizontal linear focus point (or the angle was very small), it might not be able to focus. In addition, if it exceeded the closest focusing distance of the lens, it would not be able to focus. In addition, if the focus object moves quickly and irregularly in the picture, the autofocus system may not work properly. The autofocus of the lens may also be related to the type of motor used (such as a direct current motor, an ultrasonic motor, a stepping motor, a linear motor, etc.). Different motor types have different principles and characteristics in focusing. In addition, some cameras had different focusing methods (such as split-image prism, miniature pyramid, full-screen framing, etc.), but these focusing methods were not directly related to horizontal focusing. If it was a specific device (such as the 2S lens of the Dajiang drone), damage to the focusing components (such as the focusing motor) would also cause problems with the focus. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to choose the lens of the car lens
The following factors can be considered when choosing a car lens: 1. ** Usage scenario **: - The lens design was different for different car cameras. If the functions of the car's front view, surround view, and DPS lens were different, there would be differences in design. For example, Hongjing Optoelectronics 'forward-looking, binoculars, and DPS lenses used f-tan 0 ortho-projection, focusing on the guarantee of optical main points, etc., while the surrounding lens used a Holographic model design to ensure a high density of surrounding graphics. The In-Cabin lens in the cabin would use different band options and possibly RGBI-R Confocal design. - The functions of imaging cameras (surround view, rear view, built-in camera) and sensory cameras (front view, side view camera) were different, and the lens requirements were also different. The imaging camera was used for panoramic parking, reversing, monitoring the driver's status, etc. The sensory camera was used to provide lane departure warning, blind spot monitoring, and other functions. 2. ** Optic performance index **: - The quality of a lens could be measured by optical parameters such as focal length, aperture, distortion, and resolution. For example, distortion would affect the degree of distortion of the image. In the application of vehicle vision, optical companies needed to indicate what kind of distortion model was used on the specifications because the distortion model would affect the difficulty of the algorithm and the success rate of the verification. Different lenses, such as DV, Front, LM, RVP and other conventional lenses, often used f - tan theta-orthography;Fisheye fisheye lenses often used f -theta-equidistance projection; AVI and other surround lenses often used 2*f*tan(theta-theta2) three-dimensional projection. - With the upgrade of the image quality, the number of aspheric glass lenses needed to be combined in the lens increased to reduce aberrations. The curvature and diameter of the lens could be adjusted, and the technical requirements for manufacturers increased. At present, the 8M camera needed to combine multiple aspheric glass lenses with spherical glass lenses. 3. ** Adaptability to the environment **: - The car lens had to meet the requirements of the complex use environment, such as the need to be exposed to harsh environments for a long time (strong light, sand, rain, mud, etc.), so it had to be able to meet high and low temperature impact, corrosion resistance, vibration resistance, waterproof and salt fog resistance tests. - Compared with plastic lenses, glass lenses had the characteristics of high heat resistance, low distortion, high light transmission, and high refraction index. The imaging effect was better, and the influence of thermal difference was small. It was more in line with the harsh working environment and high performance requirements of the car lens. Therefore, the car lens was mostly all-glass lens or glass-plastic hybrid lens. Generally, the front view lens, high-resolution lens, etc., which had high performance requirements, were more inclined to glass lenses. 4. ** Adaptability with the algorithm **: - Different optical distortion design models would facilitate different algorithms. For example, the optical distortion design model for different application scenarios was convenient for stitching algorithms and visual effects, and the band selection for different application scenarios was convenient for recognition algorithms and visual experience. 5. ** Anti-stray light ability **: - In practical applications, the car lens would face a variety of light environments, and it was prone to stray light. For example, the "ghost" phenomenon when taking photos with a mobile phone could also appear in the car camera. This required the lens design, material selection, and other aspects to consider reducing the generation of stray light and ghost images, such as optical design simulation, coating process, structural design optimization, and so on. 6. ** Special Function Requirement **: - For example, in order to cope with the impact of the weather on the imaging and recognition of the lens, the lens and camera module should have an automatic auxiliary heating function to quickly remove the water, ice, frost, etc. on the surface of the lens. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Is the lens long focus or short focus bright
The aperture size affected the brightness of the lens. In the case of the same aperture, the brightness of the telephoto and short-focus lens was not directly related to the focal length of the lens itself, but was related to the f-value of the aperture. The smaller the f-value, the larger the aperture, and the brighter the lens. For example, in a projection lens, the size of the aperture was inverse to the f-value. The smaller the f-value, the larger the aperture, and the brighter the projected image. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Is it better to use a fixed focus lens or a zoom lens for a novice lens?
For beginners, a zoom lens might be better. From the perspective of operational convenience, the focal length of the zoom lens could be adjusted within a certain range. For example, the common 20 - 70mm lens could be used to change the choice of shooting "far" and "close" by twisting the zoom ring. It was more convenient when shooting scenes such as cultural activities, tourism, scenery, animal activities, etc. The focal length of the fixed-focus lens was fixed, and the composition of the picture was relatively fixed. To achieve a change in the picture, the photographer could only move forward and backward to adjust the position. This was more troublesome in many scenes, such as macro shooting or shooting in the wild. It might be very inconvenient to move the position. Considering the growth stage, newcomers were generally in the initial growth stage of photography. The zoom lens had many conveniences and could be adjusted. It was more suitable for beginners to explore different shooting scenes and objects and accumulate shooting experience. When the photographer had accumulated a certain amount of shooting experience, entered a certain "level", and had his own unique control over the composition and framing, and the subject matter was relatively concentrated, he could consider using a fixed-focus lens to enhance his shooting. However, if a novice had high requirements for image quality and didn't mind adjusting the image by moving the position, a fixed-focus lens could also be chosen because the image quality of a fixed-focus lens was usually better than a zoom lens at the same price. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Nikon 7200 manual focus lens
There were some key points when using a manual focus lens on the Nikon D7200. Some manual focus lenses may not have the integrated Nikon manual lens focus prompt function. On the Nikon D7200, although the 50mmF1.8D lens did not have a body focusing motor, it could use the D7200's body motor to drive the lens focusing component to achieve autofocus. When the D7200 could not autofocus, the possible reasons included the focus distance exceeding the closest focus distance of the lens, the camera was set to manual focus mode, the focus point of the telephoto lens was not suitable, there was no obvious light and dark boundary near the focus point, the light was too weak, the focus screen was shifted, the focus screen was blocked by dust, the camera was seriously out of focus, the focus unit was damaged, and so on. In terms of manual focus, for example, when shooting star trajectories, the focus mode can choose single-point focus.(landscape, portrait, or building, etc.), adjust the camera shooting mode, choose the lighting angle, use the raw format to balance the light sense to achieve the best effect, and pay attention to the image quality. During the focusing process, gently press the shutter and wait for the focus to be completed before completely pressing the shutter to shoot; You can also turn the mode dial to M, turn the main command dial to select the shutter speed B (bulb), turn the auxiliary command dial to select the aperture, press the shutter button to start the exposure after focusing, and press the shutter button again to end the exposure. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Soft focus artistic lens
Soft focus artistic lens was a kind of lens that could produce soft focus effects. For example, the Daguerretype Achromat 2.9/64 Daguerretype soft-focus art lens had a focal length of 64mm and an aperture of f/2.9 - f/16. It used the Waterhouse aperture system, with Canon EF mount, Nikon F mount, etc., which could be used with a variety of cameras. It could shoot different effects through different apertures. For example, if you used the f/2.9 aperture, you could shoot a transparent soft focus image. If you switched to the f/5.6 aperture, you could get a sharp and clear image. In addition, there were also special aperture films, such as the Lumière aperture film, which allowed the image to be surrounded by natural soft light, and the Aquarele aperture film, which could produce the effect of oil painting strokes. Soft focus artistic lens could be used for portraits, scenery, and other photography. It could make the subject's focus clear, soft, and beautiful, and take photos with unique artistic effects, such as increasing the softness and haziness of the image, adjusting the tone, and reducing the contrast. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Focus distance, lens recommendation
The following are recommendations for different focal lengths and types of lenses, but they are not specifically filtered for the factor of focusing distance. They are for reference only: - ** APS-C wide-angle zoom lens **: Sima 10 - 18mm F2.8 DC-GN| It had an equivalent focal length of 15 - 27mm, a constant F2.8 aperture, and excellent overall image quality. It performed well in terms of distortion, dispersion, and dark angle control. - ** APS-C standard lens **: Velocix AF27mm f/1.2 Pro, suitable for Sony-E, Nikon-Z, and Fuji-X APS-C format lenses. High sharpness, good background blurring, excellent image quality from the center to the edge, almost no purple edges. - ** Ultra-wide angle fixed-focus lens **: Old Frog 10mm f/2.8 Zero-D FF. It was Old Frog's first auto-focus lens. It supported a 77mm filter and basically had zero distortion. It was fast to focus and small in size, only 420g. - ** Standard fixed-focus lens **: Florenda's NOKTA 40mm F1.2 Astral. It uses 6 sets of 8-piece lens structure (including 2 aspheric lenses). F1.2 is available with full-aperture. It has a soft and beautiful focal length. It has an all-metal lens body. The closest focusing distance is 1.3m. - ** Telephoto fixed-focus lens **: SonyFE300mmF2.8GM OSS, the lightest 328 lens of the same specifications. It weighs 1470g and can be used for hand-held shooting without any pressure. It has fast focusing speed and uses 16 sets of 20 lenses. It controls the dispersion very well. - ** Ultra-long-range fixed-focus lens **: Sima 500mm F5.6 DG GN OS| Sports, weighing only 1370g, excellent image quality, equipped with a newly developed high-speed linear motor, fast focusing, priced at 21999 yuan. - ** Professional portrait lens **: Nikon NikKOR Z135mm f/1.8S Plena, excellent overall optical quality, high resolution, beautiful out-of-focus image, multi-focus system with a step motor, fast, accurate, and quiet autofocus, weight 995g. - ** Wide-angle zoom lens **: Tenglong 17 - 50mm F/4Di III VXD, covering wide-angle to medium-focal length. The aperture is fully open, and the image quality from the center to the edge is not bad. There is a slight dark corner. - ** Micro-zoom lens **: SonyFE70 - 200mm F4macro G OSSII. Compared to the previous generation, the size is reduced by about 15%, the weight is reduced by about 46g, only 974g, and the length is shortened to 149mm. It uses an external zoom design, which improves the image quality and focusing ability, and has a new macro function. - ** Telephoto zoom lens **: Tenglong 70 - 180mm F/2.8 Di III VCXDG2. The upgraded version of Tenglong is light and large. The volume and weight are not much different. The first generation is 810g, and the second generation is 855g. The anti-shake is added, and the optical structure is re-designed. The macro is also improved. The closest focusing distance at the 70mm end is 0.3m, and the focus tracking ability is enhanced. - ** Ultra-long-range zoom lens **: Nikon S NikKOR Z 180 - 600mm f/5.6 - 6.3 VR. - ** macro lens (Nikon mount)**: Nikon Z105mm F2.8 VR S, reference price around 6050 yuan. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>