What parameters should be provided to design the lens?
The parameters that needed to be provided when designing the lens included: 1. * * Lens-related parameters **: - The number of lenses. - The type of glass. - The radius of the lens. - The thickness of the lens. - The distance between the lenses. - The diameter of each lens. 2. * * Focus related parameters **: - The effective focal length (EFL) includes the focal length of the image (the distance from the main surface of the image to the focal point of the image) and the focal length of the object (the distance from the main surface of the object to the focal point of the object). It is necessary to pay attention to the problems of the focal length being too short or too long. For example, if the focal length is too short, it will cause the field of view to be too large. If the focal length is too long, the lens will be too long and the field of view will be too small. - Back focal length (BTL, the distance from the last side of the lens in the optical system to the image plane). - The optical focal length (FFL, the distance from the first surface of the lens in the optical system to the object surface) must be distinguished from the focal length of the mechanism. - Mechanical back focal length (FTL/FFL, the distance from the last mechanical surface of the lens group to the image surface). 3. * * Overall length of the lens **: - Total optical length (the distance from the first side of the lens to the image plane). - The total length of the mechanism (the distance from the end of the lens barrel to the image surface). 4. * * Field of view (FoV)**: Including diagonal field of view (FoV-D), horizontal field of view (FoV-H), and vertical field of view (FoV-V). It refers to the largest field of view that the lens can capture. 5. * * Joules (F/NO., relative aperture)**: The ratio of the effective focal length to the diameter of the pupil. It is used to determine the brightness of the lens. 6. * * Distortion-related parameters **: Distortion is divided into TV distortion and optical distortion. It is the off-axis phase difference. It is the difference between the height of the intersection point of the off-axis point and the main ray on the image plane and the ideal (near-axis) image plane. Distortion is a function of the field of view and has nothing to do with the aperture. 7. * * relative illumination (Ri)**: The ratio of the central illumination to the peripheral illumination. If the relative illumination is too low, problems such as blurring and color distortion will occur. 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>
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>
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>
The technical parameters of the optical lens
The main technical parameters of the optical lens were as follows: 1. ** effective focal length (EFL)**: The distance from the center of the lens to the focal point. It was further 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, the field of view will be too large, resulting in distortion, difficulty in controlling the main ray angle, low contrast, serious lens bending, difficulty in correcting the phase difference, and other problems, which is not conducive to the design; if the focal length is too long, the lens will be too long, which is not conducive to the miniaturized system. If the field of view is too small, it is difficult 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)**: refers to the largest field of view that the lens 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 usually refers to the diagonal field of view of the digital camera module. 7. ** Joules (F/NO.)**: It is the ratio of the effective focal length to the diameter of the entrance pupil, which is 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 aberrations of the off-axis thin beam. 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 (near axis) image plane. It is a function of the field of view and has nothing to do with the aperture. The primary distortion changes with the cubic power of the field of view (image height), and the percentage distortion increases with the square of the image height. The distortion varies with different fields of view, and the distortion changes are non-linear. It is only the distortion of the image and does not affect the clarity of the image. Distortion is divided into TV distortion and optical distortion. TV distortion is further divided into pillow type and cylinder type. Different application scenarios have different requirements for distortion. For example, Optical-Distortion <3% is not easy to detect by the human eye, and Optical-Distortion <2% is the distortion requirement of the photographic objective lens. 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 values 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. 10. ** resolution **: It can be defined as the number of pairs of black and white stripes that can be distinguished in millimeters when the lens is used to observe the black-and-white grid pattern. When selecting a lens, the lens resolution is usually required to be slightly higher than the resolution of the picture element. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Canon lens shooting parameters
The common shooting parameters of Canon lenses were as follows: - ** Shot Type **: - "EP: Can be used with Canon's Canon's Canon '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. There were also MP-E (specialized for macro photography) and TS-E (electronic controlled shift lens), two special products. - ** focal length of lens **: A small number means a wide angle of view, and a large number means a good telescope. The focal length in the lens model is the physical focal length. For non-full frame cameras, you may need to consider the equivalent factor conversion according to the camera model. - ** Maximum Aperture **: For a zoom lens, if it is in the form of "f/2.8", it means that it is a constant aperture lens, and the entire focal length range can be set to this aperture; if it is similar to "f/3.5 - 5.6", it is a floating aperture lens, and its maximum aperture changes over the entire focal length range. - ** Lenses Grade **: L (Luxury) means Canon's high-end lenses, which are red circle lenses. These lenses usually have a red decorative ring at the front. - ** Image Stabilizer **: The IS (Image Stabilizer) logo indicates that the lens is equipped with Canon's unique image stabilizer, which can offset the image blurring caused by hand shaking within a certain range. It is commonly used in Canon's high-end professional lenses. - ** Focus motor **: - USM (Ultra-Sonic Motor): The lens using USM technology can achieve silent and fast-response autofocus. It is divided into three types: micro, ring, and NANO. - <strong></strong> - ** Other Marks **: - AL: It means that aspheric lenses are used in the lens design, which can reduce the number of lenses, reduce weight and volume, and provide better optical performance. It is used to solve the problems of glare and edge distortion in wide-angle and zoom lenses. It can also improve the optical quality of telephoto lenses. - DO: Lenses marked with this logo are equipped with multi-layer reflective lenses, which have the characteristics of fluorite and aspheric lenses. They are generally high-end lenses. - EMD: It means that the lens can open and close the aperture by electronic control. - Float: When the lens is used for close-up shooting, the lens will compensate for the aberrations at close range to obtain better image quality. - XP: The lens with this logo is a high-end professional lens. It has a focus presetting function that allows the lens to remember a certain focus distance. After setting it, it can automatically return to the set focus distance. It is also effective in manual focus mode. - FT - M: A lens with full-time manual function. You can manually adjust the focus of the lens in autofocus mode. - S-KD: It means that the lens uses S-KD glass lenses, and its optical performance is close to that of fluorite. The effect of an S-KD lens is equivalent to that of a fluorite lens. - KD: It means that the lens is made of KD glass lenses. The effect of two KD lenses is equivalent to that of a fluorite lens. - <MACRO>: This means that the lens has a strong close-up ability. - [DPS: A coating technology that optimized bokeh.] <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Nikon lens parameters setting
There were many parameters for Nikon lenses. The following are some of the main parameters: ** 1. Type of bayonet ** 1. **F mount ** - The FX-lens was suitable for all of Nikon's DSLR cameras, similar to Canon's EF-lens, while the DX-lens was suitable for Nikon's APS-C format camera, similar to Canon's EF-S lens. - Generally speaking, the price of the DV lens was more affordable and could be regarded as an APS-C (half-frame) entry-level lens, while the XP lens was a professional lens and had a higher price. However, Nikon's DV lens could be installed on a full-frame camera, but it might produce black circles or dark corners. If you didn't have a full-frame lens on hand, you could replace it after trimming the image. - Among the Nikon AF-S and AF-F lens models, the ones with the word "DK" were called "DK" lenses, and the others were "FO" lenses. The capital letter N was more commonly seen on the lens body of the FO lens. 2. ** Z-mount ** - The Z lens was suitable for Nikon micro-cameras, similar to Canon M-series lenses. ** 2. Type of motor ** 1. **AF** - This lens does not have a focus motor. You need to use a body equipped with a motor to achieve autofocus. 2. **AF - I** - It meant that the lens had a built-in motor design. 3. **AF - S** - It meant that the lens had a built-in ultrasonic motor design, which made focusing faster and quieter. Some half-frame lenses of Nikon also had this motor, which was different from Canon (Canon's similar logo was USM and was mostly used for full-frame lenses). 4. **AF - P** - It meant that the lens had a built-in stepping motor, similar to Canon's ATM logo. If there was the word (PC), it meant that the lens was a shift-axis lens. ** 3. Focus related parameters ** - Numbers such as 24 - 70mm/105mm on the lens indicate the focal length of the lens. The zooming lens was marked with the values at both ends of the focal length range, and the fixed-focus lens was represented by a single value. ** 4. Aperture related parameters ** 1. ** Maximum Aperture Value ** - For example, 1:3.5 - 5.6/1:2.8 represents the maximum aperture value. When the zoom lens had two values, they represented the maximum aperture of the wide-angle end and the telephoto end respectively; the fixed focal lens and the zoom lens used a single value to represent the constant maximum aperture. 2. ** Aperture Type ** - No Suffix meant that the lens had an aperture ring and could not provide distance information;D Suffix meant that the lens had an aperture ring and could provide distance information;G Suffix meant that the lens did not have an aperture ring but could provide distance information;E Suffix meant that the lens did not have an aperture ring, but an electromagnetic aperture could also provide distance information. E was more advanced than G. ** 5. Other parameters ** - II meant that the lens was a second-generation product. - TL, ED, PR, and so on indicate the type of lens used (Canon lenses do not indicate such information). - VR indicated that the lens had a shock absorption function, similar to Canon's IS logo. - N represents a special (nano) coated lens, which can effectively alleviate the ghostly shadows caused by red light and reduce the ghostly shadows and glare caused by the light entering the lens diagonally. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
hitachi projection lens parameters
The parameters of the Hitachi projection lens were different. For example, the parameters of one projection lens were F = 1.7 - 2.1, f = 36.8 - 47.8mm; the other was F = 1.74 - 2.08, f = 36.8 - 47.8mm; and the zooming method was a zooming lens (F = 1.7 - 2.1, f = 24 - 29mm). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Monitor the parameters of the electric zoom lens
The following are some of the parameters that might be involved in monitoring the power zoom lens: 1. ** Focus Range **: - For example, 10 - 525mm, 10 - 150mm, 10 - 230mm, etc. Different focal lengths determined the zooming ability of the lens and the applicable monitoring distance and viewing angle. For example, the focal length of a telephoto electric lens could range from tens of millimeters to hundreds of millimeters or even higher for long-distance supervision; the focal length of a wide-angle lens was shorter, and the monitoring angle was wider but closer. 2. ** optical zooming factor **: For example, there are 52x and so on. The zooming factor reflects the zooming ability of the lens within the focal length range. 3. ** Pieces **: Some of the lenses are broadcast grade with 2 million pixels. Pieces affect the clarity and image quality of the image. 4. ** Automatic focus function **: Some lenses have an automatic focus function, which helps to quickly obtain clear images at different distances. 5. ** Fog Penetration Function **: It can be used in smoggy weather to improve the visibility of the monitoring screen. 6. ** Day and night function (infrared function)**: Can be used in different lighting conditions during the day and night. It can provide fine black-and-white images at night. 7. ** Automatic temperature compensation function **: To ensure that the lens works normally in different temperature environments. 8. ** Type of serial port communication **: For example, the serial port communication of the USB 485/USB 422 is used to independently control the lens. 9. ** Adaptability to the environment **: Able to work normally from-40 ° C to 70° C, and can adapt to various environmental temperatures. 10. ** Lowest Illumination **: If there is a lens, the minimum illumination is 0.002Lux(color mode), 0.0002Lux(black and white mode), and 0Lux(infrared light on). This parameters reflect the imaging ability of the lens in low-light environments. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The parameters of a single-lens reflex camera
The following are some important settings for a DSLR camera: 1. ** Shooting Mode **: It is recommended to choose the manual mode (M). This way, you can control the shutter, aperture, sensitivity, and other parameters independently. 2. ** Video recording format and size **: If there are no special requirements, you can choose to record 1920*1080, 25 frames, MOV format of high-definition video. If there are special requirements for zooming in, you can choose 4K or other format. 3. ** Shutter Speed **: Generally, it is twice the frame rate of the video. For example, when the frame rate is 25 frames, the shutter speed is set to 50; when the frame rate is 60 frames, the shutter speed is set to 120. This way, the visual effect can be achieved. 4. ** Aperture **: The aperture size affects the depth of field of the picture. A large aperture (such as F2.8) made the picture brighter and the background blur stronger, while a small aperture (such as F11) made the picture darker and the background blur weaker. The larger the aperture value, the smaller the actual aperture. 5. ** Light sensitivity (USB)**: When there is sufficient light, the lower the USB, the better. It is not advisable to set it too high in a dark environment, otherwise it will produce noise. For example, Canon DSLR can be set to 100 during the day and 800 - 1000 at night. A high USB (greater than 2000) will produce obvious noise and it will be difficult to repair later. 6. ** Color temperature (white balance)**: adjust to manual mode. Generally, it is recommended to adjust the color temperature between 4900 and 5300. The higher the color temperature, the more yellow the screen will be, and the lower the color temperature, the more blue the screen will be. 7. ** Focus **: If you have good manual operation ability, you can try to manually focus and select the focus point. Novice or for convenience, you can use the automatic intelligent autofocus. However, it is recommended to practice manual focus more if possible. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Industrial lens parameters detailed explanation
The parameters of an industrial lens included the following important aspects: ##1. Focus (EFL) 1. ** definition and essence ** - The focal length is the distance from the main light point of the optical system to the focal point. The distance from the topmost lens to the back focal point is called the back focal length, and the distance from the bottommost lens to the front focal point is called the front focal length. It was an indicator of the ability of an optical system to converge or diverge light. 2. ** Relationship with field of view ** - For the same sensor, the longer the focal length of the lens, the smaller the field of view, and the smaller the field of view. Conversely, the smaller the focal length, the larger the field of view, and the larger the field of view. ##2. Field of View 1. ** Meaning ** - It refers to the range of the image that the lens can capture, usually expressed in terms of field of view. ##3. Magnification 1. ** Concepts ** - Magnification refers to the ratio of the size of the image to the size of the object. ##4. Chip size 1. ** Selection Principle ** - To choose a lens with a larger compatibility, if the target surface of the CCD-chip is 1 ", the lens should at least use a lens with a maximum compatibility of 1". A 2/3 "lens is not suitable. ##5. Numeric Aperture UA 1. ** Impact on the camera ** - It would affect the resolution and aperture of the lens. The larger the UA value, the better the lens resolution and aperture. The resolution calculation formula is: resolution = 0.61* Lambda/UA (Lambda is the light source's wavelength). At the same time, effective FNO = optical magnification/(2xUA). ##6. Aperture Number (F.No) 1. ** Concepts ** - The aperture number (F.No) was the ratio of focal length (EFL) to the entrance pupil (D, the image of the aperture in the object space), which was F.No = EFL/D. 2. ** Impact on the picture ** - The size of the F.No number would affect the brightness of the screen, the depth of field, and the sensitivity of the installation. ##7. Working Distance WD 1. ** Concepts ** - It refers to the distance between the bottom of the lens and the surface of the object. In the machine vision optical system, the required space had to consider the length of the camera lens group itself and the working distance of the lens. If the space could not satisfy the sum of the two, it was necessary to consider changing the working direction of the prism or re-designing the optical system. ##8. DOF 1. ** Relationship with focal length and working distance ** - The relationship between depth of field and focal length was that the longer the focal length, the smaller the depth of field, and the shorter the focal length, the greater the depth of field. The relationship between depth of field and working distance was that the shorter the working distance, the closer the lens was to the object, and the smaller the depth of field. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>