The lens parameters are good or bad
The judgment of lens parameters mainly involved the following aspects: ** 1. Focus related ** 1. ** Fixed focus and zooming ** - The focal length of the fixed-focus lens was fixed (such as 50mm) and had a fixed shooting angle. Fixed focus lenses often had certain advantages in terms of optical performance, and the image quality might be better. - The focal length of the zoom lens was variable (such as 24 - 70mm), and the shooting angle could be changed by adjusting the lens. It was convenient, but at the same price, it might be slightly inferior to a fixed-focus lens in terms of image quality. 2. ** Relationship between angle of view and focal length (for the same camera)** - The larger the focal length number, the smaller the angle of view. It could enlarge the distant scene, suitable for close-up, long-distance or telephoto shooting scenes, such as shooting sports, birds, and so on. - The smaller the focal length, the wider the angle of view, allowing the picture to contain more information. It was suitable for shooting scenes that required a deep sense of depth, such as culture and vlogs. However, the quality of the lens could not be judged solely based on the focal length range. For example, the 18 - 200mm lens covered a larger focal length range than the 18 - 135mm lens, but it could not be directly considered that the 18 - 200mm lens was better. 3. ** equivalent focal length (different camera format)** - Lenses with the same focal length had different angles of view on different camera frames. In order to facilitate comparison, the concepts of equivalent coefficient and equivalent focal length (equivalent focal length = focal length × equivalent coefficient) were introduced. When different frame cameras were equipped with the same focal length lens, the effect of the equivalent focal length on the shooting angle needed to be considered. ** 2. Aperture related ** 1. ** Aperture size indicates ** - The maximum aperture of the lens could be written in many ways, such as 1:2.8, f/2.8, and F2.8. The smaller the number, the larger the aperture, and the larger the number, the smaller the aperture (such as F1.4>F2.8>F4). 2. ** Impact on the virtual reality and depth of field of the image ** - For the same camera and the same focal length, the larger the aperture, the shorter the depth of field. In portraits and still life shots, it was easier to blur the background and highlight the subject. - A large aperture could help increase the shutter speed, help to freeze high-speed moving subjects or improve the success rate of hand-held shooting in low-light environments, but a large aperture lens did not necessarily have better image quality. 3. ** Aperture in a zoom lens ** - If the focal length of the zoom lens is 1 number (such as F2.8), it means that it can reach F2.8 aperture (constant aperture) over the entire focal length range; if the lens aperture is 2 numbers (such as F3.5 - 5.6), it means that during the zooming process, the maximum aperture of the lens will change (floating aperture). Generally speaking, a constant aperture lens was more expensive than a floating aperture lens. ** 3. MTF value (module transfer function)** 1. ** Meaning ** - The MTF value was a comprehensive evaluation of the sharpness, contrast, and resolution of the lens, which was also an evaluation of the overall resolution. 2. ** Value interpretation ** - An MTF value of 0.8 or above meant that the lens 'performance had entered the "excellent range," but it was not necessarily a good lens overall. If the MTF value at the center of the circle was less than 0.6, it was definitely not a good lens. However, it should be noted that MTF charts should not be used to compare lenses with different focal lengths, different frames, fixed focus, and zooming lenses, nor should MTF charts be used to compare lenses from different manufacturers under the same focal length. This was because MTF charts published by various manufacturers were obtained under different test conditions and were not comparable. Read more exciting novels for free
Single lens reflex lens parameters
The angle of view of the medium focal length lens was between 40 degrees and 18 degrees, and the focal length range was between 61mm and 135 mm. The angle of view of a standard/medium-focus lens was about 40 - 55 degrees. In terms of optical characteristics, the photos taken at this focal length had the least distortion and could accurately reflect the shape of the subject. It was also relatively easy to design a large aperture. Different models of medium-focal lenses had different performance parameters in terms of distortion, dispersion, resolution, contrast, and so on. For example, the Olympus OM Zuiko auto-macro 90mm f/2.0 lens had an actual focal length of 90.44mm, an aperture of f/2.04, a pincushion-shaped distortion of 0.47%, and an edge loss of 0.3 stops at f/5.6. Minolta MC Rokkor -85mm f/1.7 lens, the actual test focal length was 85.6mm, with 0.5% barrel distortion, etc. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Analysis of lens parameters
The important parameters of the lens were mainly focal length and aperture. The following is an analysis of them: ** 1. Focus ** 1. ** Fixed focus and zooming ** - The focal length of a fixed-focus lens was a fixed number, such as 50mm, which had a fixed angle of view. If the photographer wanted to change the width of the picture or the size of the distant view, he could only do so by moving back and forth. The optical design and mechanical structure of the fixed-focus lens were simple. It could achieve higher image quality, larger aperture, and lighter at a lower cost. However, it was less adaptable in a working environment where the field of view needed to be changed quickly. - The focal length of a zoom lens was a range represented by two numbers, such as 24 - 70mm. The angle of view could be changed by adjusting the lens. The field of view was variable and was suitable for quick shots of moving scenes. A zoom lens was more convenient to use than multiple fixed-focus lenses, but the structure was complicated and the light path design was difficult. Compared to fixed-focus lenses, it was more expensive, the image quality was poor, and the aperture was smaller. 2. ** Relationship between focal length, shooting angle, and image content ** - For the same camera, the larger the focal length number, the smaller the angle of view, and the larger the distant scene; the smaller the focal length number, the wider the angle of view, and the more information the picture could contain. - Different focal lengths had different shooting purposes: - The wide-angle range (usually <35mm) was suitable for shooting humanities and vlogs, which could highlight the depth. - The medium focal length (usually 36mm-134mm) was suitable for portraits or travel photography. - The telephoto end (usually> 136mm) is suitable for shooting long-range shots, sports, flying birds, or expressing a small sense of depth. 3. ** equivalent focal length ** - Lenses with the same focal length had different angles of view on different frame cameras. For this reason, the concept of equivalent coefficient and equivalent focal length was introduced (equivalent focal length = focal length × equivalent coefficient). In some cases (such as when an APS-C format camera is equipped with a full-frame lens or an APS-C format camera is equipped with an APS-C format lens), the equivalent focal length needs to be calculated. ** 2. Aperture ** 1. ** The expression and meaning of the aperture size ** - The maximum aperture of the lens could be written in many ways, such as 1:2.8, f/2.8, and F2.8. The smaller the aperture number, the larger the aperture, and the larger the number, the smaller the aperture (such as F1.4>F2.8>F4). For a zoom lens, if the aperture is a number (such as F2.8), it means that the F2.8 aperture can be achieved over the entire focal length range. If the aperture is two numbers (such as F3.5 - 5.6), the maximum aperture of the lens will change during zooming. 2. ** The effect of the aperture on the image ** - Aperture mainly affected the image's reality. In the same camera and the same focal length, the larger the aperture, the lighter the depth of field. In portraits and still life shots, it was easier to blur the background and highlight the main body. - Aperture, shutter, and sensitivity together constituted the three elements of exposure. A large aperture could increase the shutter speed and help to freeze high-speed moving subjects or increase the success rate of hand-held shooting in low-light environments. 3. ** Permanent Aperture and Non-Permanent Aperture ** - A constant aperture usually means that the zoom lens can use its nominal maximum aperture at all focal lengths, such as 24 - 70mmF2.8. Generally, it can achieve better image quality. When the aperture is set to the maximum, the zooming operation will be carried out. The constant aperture lens will not affect the exposure. The disadvantage was that if it was a wide-angle lens with a constant large aperture, it would be relatively expensive. - Non-constant aperture (also known as floating aperture) refers to the aperture of the lens that changes with the focal length, such as 18 - 300mmF3.5 - 5.6. Its advantage was that the lens was small in diameter, low in weight, and cheap, but the focusing speed was relatively slow. Due to the small aperture, it was not conducive to taking shallow depth of field photos. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Dajiang lens parameters
The following are some of the Djiang lens parameters: - **DJI PL PZ 17 - 28mm T3.0 ASHH lens **: - The lens frame was full frame (36* 24mm). The lens was used as a movie lens. The lens type was zoom. The lens structure was 11 sets of 13 pieces. The lens mount was a PL mount. The filter size was 67mm. - In terms of optical parameters, the maximum aperture was T3.0, the minimum aperture was T22, the focal length range was 17 - 28mm, the closest focusing distance at the 17mm end was 0.19m, and the closest focusing distance at the 28mm end was 0.26m. - The diameter of the lens was 78mm, the length of the lens was 117.2 mm, the weight of the lens was about 520g, the working temperature was-10 ° C to 55 ° C, the storage temperature was 10 ° C to 35 ° C, and the storage humidity was 45% to 75%. - **DJI TL 75mm F1.8 lens **: It is suitable for the 75mm medium telephoto focal length of Zenith X9 - Air lens. The F1.8 large aperture can capture a richer depth of the picture. It has a shallow depth of field and a larger amount of light. It can enhance the performance of the main body and the night scene. It weighs only 269 grams. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The optical parameters on the lens
The following is some common optical parameters on the lens: 1. ** effective focal length (EFL)**: The distance from the center of the lens to the focal point. It could be divided into image focal length (the distance between the main surface of the image and the focal point of the image) and object focal length (the distance between the main surface of the object and the focal point of the object). If the focal length is too short, it will cause the field of view to be too large, causing distortion, difficulty in controlling the angle of the chief ray, low contrast, serious lens bending, difficulty in correcting the phase difference, and other problems. If the focal length is too long, the lens will be too long, which is not conducive to the miniaturized system. Moreover, the field of view is too small to meet the user's needs (FoV>60°). 2. ** Total length of lens (TL)**: It is divided into optical length (the distance between the first surface of the lens and the image surface) and mechanism length (the distance between the end of the lens barrel and the image surface). 3. ** Back focal length (BTL)**: The distance from the last side of the lens in the optical system to the image plane. 4. ** Front focal length (FFL)**: The distance from the first surface of the lens to the object surface in the optical system must be distinguished from the back focal length of the mechanism. 5. ** Mechanical back focal length (FTL/FFL)**: The distance from the last mechanical surface of the lens group to the image surface. 6. ** Field of View (FoV)**: The largest field of view that the camera can capture. It can be divided into diagonal field of view (FoV-D), horizontal field of view (FoV-H), and vertical field of view (FoV-V). The diagonal field of view is the largest, followed by the horizontal field of view, and the vertical field of view is the smallest. The so-called field of view refers to the diagonal field of view of the digital camera module. The size of the field of view was related to the focal length. Generally, the larger the field of view, the shorter the focal length. 7. ** Joules (F/NO.)**: It was the ratio of the effective focal length to the diameter of the pupil, which was used to determine the brightness of the lens. Under the premise of ensuring the same aperture, the shorter the focal length, the smaller the relative aperture should be. In general, the smaller the F/#, the larger the aperture. 8. Distortion: It is the off-axis phase difference. It is the height difference between the intersection point of the off-axis point and the main ray on the image plane and the ideal (paraxial-like) image plane. It is a function of the field of view and has nothing to do with the aperture. Distortion was divided into TV distortion and optical distortion. TV distortion was further divided into pillow type and cylinder type. Distortion is the image quality that users can easily feel. Different application scenarios have different requirements for distortion. For example, Optical-Distortion <3% is not easy to detect by the human eye, and the objective lens generally requires Optical-Distortion <2%. 9. ** relative illumination (Ri)**: The ratio of the central illumination to the peripheral illumination. If the contrast was too low, the center of the image would be bright and the surroundings would be dark (vignette phenomenon, commonly known as dark corners), which would also cause color distortion. The Ri is directly proportional to COS4 (semi-fov). Different semi-fov correspond to different theoretical values of the Ri. When the Ri<50%, the human eye can distinguish it. In serious cases, the four corners of the picture will be completely black. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Canon lens parameters
Canon lenses had many parameters: ** 1. Type of bayonet ** 1. **EF** - It can be used directly on Canon's Canon's Canon 'Canon's Canon' Canon 2. **EF - S** - Canon's APS-C frame DSLR lens could not be directly installed on a full-frame DSLR. It could be used on the Eos-M series micro-lens and the Eos-R full-frame micro-lens through the transfer ring. 3. **EF - M** - Canon's Canon 'Canon's Canon's Canon 4. **RF** - Canon's Canon 5. **MP - E** - For macro photography, only MP-E 65mm f/2.81 - 5x. 6. **TS - E** - The electronic control shifted the lens. ** 2. Focus ** - The focal length in the lens model was the physical focal length. Standing in the same position, a small focal length meant a wide field of view, and a large focal length meant a good range of vision. For non-full-frame cameras, the actual use may need to consider the equivalent factor conversion according to the camera model. For example, the focal length range of the lens was 70 - 200mm, the angle of view at the 70mm end was relatively narrow, and the telescope ability at the 200mm end was better. ** 3. Maximum aperture ** 1. ** Permanent Aperture ** - For example,"f/2.8" could be set to this aperture value over the entire focal length range. For example, the EF70 - 200mm f/2.8 lens was a constant aperture lens. 2. ** Floating Aperture ** - Two numbers like "f/3.5 - 5.6" indicated that the maximum aperture changed over the entire focal length range. ** 4. Screen Level Identification ** - **L (Luxury) logo ** - It would only appear in Canon's professional lens identification information. It was the logo of the top Canon civilian lens. These lenses usually had a red decorative ring on the front end (red circle head). ** 5. Function ID ** 1. **IS (Image Stabilizer)** - This type of lens was equipped with Canon's unique image stabilizing device, which could offset the image blurring caused by hand shaking within a certain range. It was commonly used in Canon's high-end professional lenses. 2. **USM (ultrasonic motor)** - The lens using USM technology could achieve silent and fast-response autofocus. It was divided into three types: micro, ring, and NANO. There was also the STMs (Stepping Focus Machines), which were divided into two types: gear type and lead screw type. 3. **AL (Aspherical lens)** - It showed that the lens was designed with aspheric lenses to reduce the number of lenses. While reducing the weight and volume, it could provide better optical performance. It could solve the glare and edge distortion problems in wide-angle and zoom lenses, and it could also improve the optical quality of telephoto lenses. 4. **DO (Diffraction Optics)** - Lenses marked with this logo were equipped with multi-layered diffusing optical lenses, which had the characteristics of both fluorite and aspheric lenses. They were generally high-end Canon lenses. 5. ** DPS (a coating technology that optimized bokeh)** - It was commonly used in some Canon lenses to enhance the bokeh effect. 6. ** S-ud (S-ud glass) and UD (UD glass)** - The optical performance of S-KD glass was close to that of fluorite. The effect of one S-KD lens was equivalent to that of one fluorite lens, and the effect of two KD lenses was equivalent to that of one fluorite lens. These labels indicated that the lenses used the corresponding glass lenses. 7. **EMD (Electromagnetic Aperture)** - Lenses with this technology could open and close the aperture by electronic control. 8. **Float (Floating Function)** - When shooting at close range, the floating lens would compensate for the aberrations at close range to obtain better image quality. 9. ** CP (Focus Preset)** - It was Canon's high-end professional lens logo. The focus preset function allowed the lens to remember a certain focus distance. After setting the distance, the lens could automatically return to the set focus distance. This focus recovery function was even effective in manual focus mode. 10. ** ft-m (full-time manual)** - Canon lenses were equipped with full-time manual operation. The focus of the lens could be adjusted manually in the AF-mode. 11. ** Marco/macro ** - It means that the camera has a strong close-up ability. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Microscope objective lens parameters
The parameters of the microscope objective lens mainly included the following aspects: 1. ** Magnification **: It can be divided into low-power objectives (such as 2x, 4x/5x, and 10x), medium-power objectives (such as 20x, 40x), and high-power objectives (such as 60x/63x, 100x). Different magnifying lenses used different media. High power lenses (60x and 100x) often used oil to obtain high resolution, while lenses with lower magnifying powers used air as the medium. 2. ** Observation method **: There are many types of microscope objectives. The common observation methods marked on the lens shell are: FF (bright-field), TF (dark-field), PL (phase contrast), Po (polar light), DIC (differential interference), FF (fluorescence observation, such as blue, green, purple, etc.), UVFO (ultraviolet-fluorescence observation), etc. 3. ** Chromatic Deviation correction ability **: - Achromatic objective lens: It can only correct the color difference of red and blue light. - Semiapochromatic objective (TL): Able to correct the color difference of red, green, and blue light. - Apoachromatic objective lens (Apo): It can correct the color difference of red, green and blue light twice, and can correct the spherical aberrations of red and blue light at the same time. 4. ** Flat-field correction function **: Choose an objective lens with flat-field correction function (marked with Plan) for better imaging effect. For example, a flat-field achromatic objective (Ach) could be used to view transparent sections; a semi-apochromatic objective (TL) could be used to view fluorescence, which had a long working distance and could be used to observe glass slips and petri dishes; a full-apochromatic objective (Apo) could be used for better imaging effects. However, Apo objectives did not have a long working distance and were only suitable for viewing glass slips, not for viewing thick samples such as petri dishes or culture bottles. 5. ** Numeric Aperture (NAC value)**: This is the main parameters of the objective lens and the condensing device. It is directly proportional to the resolution of the microscope, directly proportional to the magnifying power, and inverse proportional to the depth of field. UA = n * sin alpha. Under the same amplification, the higher the UA, the better. In the case where the working distance is satisfied, the objective lens with a high UA value should be selected. The numerical aperture of the dry objective lens was 0.05 - 0.95, and the numerical aperture of the oil-immersed objective lens was 1.25. 6. ** Working Distance (WD)**: - Ordinary working distance objective lens: The working distance is small, and the slices can be observed, but the petri dish cannot be observed. - [Long working distance objective lens: Used for inverted microscope. It can be used for microscopic examination of tissues, suspension, and other materials.] 7. ** Glass slide thickness **: After the optical type of the objective lens (infinity/0)(210/0), the number behind the slash represents the applicable glass slide thickness. For example,(infinity/0.17)(210/0.17), the applicable glass slide thickness is 0.17 mm. The objective lens with a higher NAC value was more sensitive to the thickness of the cover glass. Some objective lenses with high NAC values and those with long working distances had an adjustment ring for the thickness of the cover glass, which could be used for observation in petri dishes. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Analysis of Canon lens parameters
Using Canon's EF70 - 200mm f/2.8L IS III USM lens as an example to analyze Canon's lens parameters: 1. ** Type of lens ** - "EP: Can be used directly on Canon's Canon 'Canon' - ESF-S: Canon's APS-C frame single-lens reflex lens. It can't be directly installed on a full-frame single-lens reflex. It can be used on the eos-M series micro-lens and eos-R full-frame micro-lens through the transfer ring. - "ESF-M: Canon's Eos M series micro-lens. It cannot be used on other Canon cameras. - <<PR>: Canon's Eos R series full-frame micro-lens. It cannot be used on other Canon cameras. In addition, there were also two special products, MP-E (for macro photography, only MP-E 65mm f/2.81 - 5x) and ts-E (electronic control shift lens). 2. ** Focus of the lens ** - For example, 70 - 200mm represents the focal length range of the lens. Standing in the same position, a small focal length meant a wide field of view, and a large focal length meant a good range of vision. Note that the focal length in the lens model is the physical focal length. In actual use, consider whether to convert it according to the camera model (non-full-frame cameras need to x the equivalent factor). 3. ** Maximum Aperture ** - For example, f/2.8 represented the maximum aperture. If it was "f/2.8", it meant that this was a constant aperture lens, which meant that the aperture could be set to "f/2.8" over the entire focal length range. If it was two numbers like "f/3.5 - 5.6", it was a floating aperture lens, which meant that the maximum aperture over the entire focal length range was changing. 4. ** Screen Level Flag ** - L: This lens is Canon's high-end lens (commonly known as the red circle lens). 5. ** Image stabilization function logo ** - IS: It means that this lens has anti-shake function, which can improve the success rate of hand-held shooting. 6. ** Algebra ID of the product ** - III: It means that this lens is the third generation of the same specifications (focal length, aperture, whether it has anti-shake). 7. ** Focus motor logo ** - USM: ultrasonic focusing motor, divided into three types: miniature, ring, and NANO. There was also the ST M, which was a step focusing motor. It was divided into two types: gear type and lead screw type. 8. ** Other Marks ** - You might also see symbols such as macro (with strong close-up capabilities), DO (a special optical component), and DPS (a coating technology that optimized bokeh). In addition, different lenses had their own parameters. For example, Canon's RF135mm F1.8LIS USM lens had a focal length of 135mm, a lens aperture range of f/1.8 - f/22, nine aperture blades (circular aperture blades), and a lens structure of 12 groups of 17 blades.(Including 3 pieces of KD lenses), the driving system is NANO USM ultrasonic motor, the hand shake compensation effect is about 5.5, the closest focusing distance is 0.7m, the maximum magnification is 0.26, the filter aperture is 82mm, the lens size is 89.2mm×130.3m, the weight is about 935g, and the bayonet type is RF. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Details of the camera lens parameters
The main parameters of the camera lens include focal length and aperture. The following is a detailed introduction: ** 1. Focus ** 1. ** Fixed focus lens ** - "definition: A lens with a fixed focal length. The common focal lengths are 10mm, 24mm, 35mm, 50mm, 85mm, 100mm, 135mm, etc. - Special traits: - The optical design and mechanical structure are simple, and the high image quality can be achieved at a low manufacturing cost. - It had a larger aperture and a lighter lens. - Because the focal length could not be changed, the adaptability was poor in scenes that required a quick change in the field of view. When shooting, one often had to move their position to change the framing range. 2. ** Zooming lens ** - "definition: A lens with a focal length that can be changed within a certain range, such as 12 - 24mm, 24 - 70mm, 70 - 200mm, etc. - Special traits: - The field of view could be changed, which was suitable for quick shots of active scenes. It was more convenient than carrying multiple fixed-focus lenses. - The structure was complicated, and the design of the optical path was difficult. Compared to the fixed-focus lens, the price was higher, the image quality was slightly worse, and the aperture was relatively small. - Different focal lengths: - Wide-angle range (usually <35mm): suitable for shooting culture, vlog, can highlight the sense of depth. - Medium focal length (usually 36mm-134mm): Often used for portraits or travel photography. - Telephoto end (usually> 136mm): suitable for shooting long-range shots, sports, flying birds, or expressing a sense of depth. ** 2. Aperture ** 1. ** Aperture expression and size relationship ** - The aperture value was marked with the letter f, such as 1:2.8, f/2.8, and F2.8. The smaller the f value, the larger the aperture, such as F1.4>F2.8>F4. The smaller the f value, the more blurred the background of the subject and the lighter the depth of field. At the same time, a large aperture also meant that the amount of light entering was larger. 2. ** Permanent Aperture and Non-Permanent Aperture (Floating Aperture)** - ** Permanent Aperture ** - For a zoom lens, the nominal maximum aperture can be used in all focal lengths, such as 24 - 70mmF2.8, 24 - 105mmF4, etc. - Special traits: - Generally, it can achieve better image quality (compared to a floating aperture lens). - Zooming when the aperture is set to the maximum will not affect the exposure. - If it was a wide-angle lens with a constant large aperture, it would be relatively expensive. - ** Non-constant Aperture (Floating Aperture)** - The aperture of the lens will change with the focal length, such as 18 - 300mmF3.5 - 5.6, 100 - 400mmF4.5 - 5.5, etc. - Special traits: - The lens was small in diameter, light in weight, and cheap. - The focusing speed was relatively slow. Due to the small aperture, it was not conducive to taking shallow depth of field photos. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The main parameters of the camera lens
The main parameters of the camera lens were as follows: ** 1. Focus related ** 1. ** Fixed focus lens ** - The focal length was fixed. The common focal lengths were 10mm, 24mm, 35mm, 50mm, 85mm, 100mm, 135mm, etc. - The optical design and mechanical structure of the fixed-focus lens were simple. It could achieve high image quality, large aperture, and lighter at a lower cost. However, because the focal length could not be changed, it was not suitable for scenes that required rapid changes in the field of view. For example, when shooting dynamic scenes, the photographer might need to move his position to adjust the viewing range. 2. ** Zooming lens ** - The focal length can be changed within a certain range, such as 12 - 24mm, 24 - 70mm, 70 - 200mm, etc. - The advantage was that the field of view could be changed, and there was no need to change the lens to take photos of different scenes. It was suitable for quick shots of active scenes. However, its structure was complicated and the design of the optical path was difficult. Compared to a fixed-focus lens, the price might be higher, the image quality might be slightly worse, and the aperture might be smaller. ** 2. Aperture related ** 1. ** Constant-aperture lens ** - For the zoom lens, the nominal maximum aperture can be used in all focal lengths, such as 24 - 70mmF2.8, 24 - 105mmF4, 50mmF1.2, 85mmF1.4, etc. - The constant aperture lens would not affect the exposure when zooming at the maximum aperture, and generally could achieve better shooting quality. However, if it was a wide-angle lens with a constant large aperture, it would be relatively expensive. 2. ** Non-constant aperture lens (Floating aperture lens)** - The aperture of the lens would change accordingly with the focal length, such as 18 - 300mmF3.5 - 5.6, 100 - 400mmF4.5 - 5.5, etc. In addition, 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. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Sony DSLR lens parameters
The following are some of the parameters related to common Sony-grade DSLR lenses: ** 1. Focus ** 1. ** SonyMDT18 - 135mmF3.5 - 5.6Sam**: The focal length range is 18 - 135mm. 2. ** PE PZ 28 - 135mm F4G OSS**: focal length 28 - 135mm. 3. ** ESF-S 18 - 200**: The focal length range is 18 - 200mm. 4. ** Sony70 - 400mm F4 - 5.6G SSM**: The focal length range is 70 - 400mm. 5. ** SonyFE24 - 240mmF3.5 - 6.3OSS**: The focal length range is 24 - 240mm. 6. ** SonyFE24 - 70mmF2.8GM**: The focal length is 24 - 70mm. 7. ** SonyFE24 - 105mmF4 **: The focal length range is 24 - 105mm. ** 2. Maximum aperture ** 1. ** SonyMD18 - 135mm F3.5 - 5.6Sam**: It is a floating aperture lens, and the maximum aperture changes between F3.5 - 5.6. 2. ** PE PZ 28 - 135mm F4G OSS**: A constant aperture lens with a maximum aperture of F4. 3. ** ESF-S18 - 200**: The maximum aperture is F2.8. 4. ** Sony70 - 400mm F4 - 5.6G SSM**: It is a floating aperture lens, and the maximum aperture varies between F4 - 5.6. 5. ** SonyFE24 - 240mmF3.5 - 6.3OSS**: It is a floating aperture lens, and the maximum aperture changes between F3.5 - 6.3. ** 3. Identification and characteristics of the lens type ** 1. ** PE **: E-mount full-frame lens, suitable for all E-mount devices. 2. **E**: E-mount APS-C frame lens, can be installed on all E-mount devices, but when paired with a full-frame camera, there will be frame trimming by default (only the central part of the CPU is used). If the image is not trimmed, there will usually be obvious halation or black blocking. 3. **G**: Inherited from Minolta's high-end lens logo, most of them have nano-coating. 4. **ZA**: A lens product jointly developed by Sony and Zeiss. The lens body and packaging have the double logo of Sony and Zeiss, all with T* coating. The lens may also have the words representing the lens structure (such as Warrio-Tessar, Planer, Distagon, Sonnar, etc.). There is no new product since July 2016. 5. GM (G-Master or "G-Master"): It was the highest-end lens product line from Sony, and all of them were nano-coated. ** 4. Other characteristics ** 1. ** PE PZ 28 - 135mm F4G OSS**: It has a power zoom function, which can provide smooth angle conversion and anti-shake function. 2. ** ESF-S18 - 200**: Automatic focus and anti-shake support. 3. ** Sony70 - 400mmF4 - 5.6G SSM**: It has SSM (ultrasonic motor), which is good for autofocus operation. 4. ** SonyFE24 - 240mmF3.5 - 6.3OSS**: With OSS (optical image stabilization system). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>