How to choose the best focal length for industrial lenses
Choosing the best focal length for industrial lenses required a combination of many factors: 1. ** Consider the size of the object to be measured and the required magnification **: - If you want to shoot smaller objects and need a higher magnification, you should choose a lens with a longer focal length. For example, when shooting fine objects such as tiny electronic components, a longer focal length helped to magnify the object so that the details could be observed more clearly. - If you need to shoot a larger object or a wider field of view, it is suitable to choose a lens with a shorter focal length. For example, when shooting the overall appearance of large industrial equipment, a short focal length could cover a wider field of view. 2. ** Combining working distance and field of vision **: - Given the size of the camera's CCTV, the working distance (WD), and the field of view (FoV), the focal length of the required lens can be calculated according to the formula: focal length f = {working distance/long side (or short side) of the field of view}× long side (or short side) of the CCTV. When the ratio of the long side and the short side of the field of view is less than 4:3, the short side is used for calculation; when it is greater than 4:3, the long side is used for calculation; when it is equal to 4:3, both the long side and the short side can be calculated. 3. ** Considering the size of the camera's CCD-sensor **: - Because there was a standard for the size of the CCD-chip, different sizes of CCD-chips with different focal lengths of the lens would produce different imaging effects. The maximum CCD-size that the lens could support should be greater than or equal to the size of the CCD-chip of the camera. 4. ** Take into consideration the imaging effect **: - The resolution of the same camera would be different if different focal lengths were used. The appropriate focal length should be selected according to the requirements of the imaging resolution to ensure a clear and high-quality image. Read more exciting novels for free
How to choose the focal length of the surveillance camera
The following aspects could be considered when selecting the monitoring focal length: * * 1. Choose according to the monitoring range ** 1. * * Small monitoring range and large viewing angle **: For example, in a family living room or small shops, you can choose a surveillance camera with a smaller focal length. For example, a camera with a focal length of 3.6mm or 4mm can have a viewing angle of 75 °-90 °, an effective monitoring distance of more than 5 meters, and can cover a space of 40 - 80 square meters. 2. * * Large monitoring range (10m * 10m or more)**: You need to choose a surveillance camera with a larger focal length, but a larger focal length will reduce the monitoring angle. To achieve complete monitoring, you can consider using a cloud platform ball machine or installing multiple surveillance cameras. 3. * * Surveillance range is fixed and very far away (such as monitoring a parking lot 30 meters away)**: You need to choose a camera with a larger focal length, such as a surveillance camera with a 12mm or higher. * * 2. Choose based on the usage scenario ** 1. * * Narrow space (such as garage, storage room, etc.)**: It is recommended to choose 2.8mm focal length, and the best monitoring distance is within 3 meters. 2. * * Home or small shop environment **: It is recommended to choose 4 mm focal length, and the best monitoring distance is 3 - 5 m. 3. * * Family courtyard, balcony, doorway, etc. **: 6mm focal length is recommended. 4. * * A wide outdoor area without high requirements for details **: A camera with a 4mm focal length is more suitable. 5. * * Need to capture detailed information from a distance (such as license plate number or facial features)**: A camera with an 8mm focal length is more suitable. In addition, the field of view of the surveillance camera is determined by the width, height, and distance from the surveillance camera. Once the scene to be monitored is determined, the correct choice of the focal length of the lens is also affected by the size of the scene to be monitored, the distance between the camera and the scene, and the size of the camera imagers (such as 1/3 ", 1/2", 2/3 "or 1 "). The calculation method is: f = vD/V or f = hD/H (where, f represents the focal length. When f = vD/V, v represents the vertical height of the CCD-target surface, D represents the distance from the lens to the scene, and V represents the height of the object being observed; when f = hD/H, h represents the horizontal width of the CCD-target surface, D represents the distance from the lens to the scene, and H represents the width of the object being observed). After calculating the focal length value, if there was no corresponding focal length lens, one could choose a similar model according to the product catalog. Generally, one would choose a smaller lens than the calculated value, so that the viewing angle would be larger. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to choose the focal length of an optical lens
There were many factors to consider when choosing the focal length of an optical lens: 1. ** Scene and Distance ** - ** Close-range and wide-range scenes **: For indoor shooting, when the distance is close and the shooting range is large, it is suitable to choose a wide-angle lens, such as a 24mm or 35mm focal length lens. - ** Daily Record Scenes **: If you prefer to record daily life photos and want to shoot a friendly and natural effect, you can choose a standard lens. 50mm focal length is more suitable. - ** Portrait shooting scene **: If you like portraits, you can choose from three classic portrait lenses, 35mm, 50mm, and 85mm, according to your favorite shooting distance and lens perspective effect. - ** Long-distance shooting scenes **: For long-distance scenes such as flowers, birds, birds, and sports events, you should choose a telephoto lens, such as 135mm and 200mm focal lengths. 2. ** Image Effect Requirement ** - ** Image size **: The longer the focal length of the lens, the larger the image. - ** Distortion effect **: When the shooting field of view is large, the lens may be distorted. When the working distance was fixed, the larger the field of view required for shooting, the shorter the focal length of the lens used, and the more obvious the degree of distortion. When a telephoto lens was used to shoot a portrait, the longer the focal length, the less obvious the distortion effect of the lens image. It could capture a more natural image of the face. - ** X-ray effect **: Different focal length lenses have different x-ray effects when shooting portraits. You can choose the lens with the appropriate focal length according to your preferences to meet your needs. 3. ** Relationship with other optical parameters ** - ** Field of view **: Generally, the focal length is related to the field of view. The larger the focal length, the smaller the field of view. If you want a larger field of view, you need to choose a shorter focal length lens; if you want to narrow the field of view and highlight the subject, you need to choose a longer focal length lens. - ** Depth-of-field **: Depth-of-field is related to focal length. Usually, a lens with a short focal length has a large depth of field. If you want a large depth of field effect, you can choose a short focal length lens; if you want a small depth of field to highlight the main body, you can choose a long focal length lens. - ** In terms of relative brightness **: The relative aperture (related to the focal length, the relative aperture refers to the ratio of the effective aperture of the lens to the focal length) mainly affects the illumination of the image plane. Under normal circumstances, the larger the relative aperture, the brighter the image plane will be. 4. ** Type of lens (fixed focus and zoom)** - ** Fixed focus lens **: The focal length is fixed, such as a 50mm F1.8 fixed focus lens. A fixed-focus lens might have an advantage in terms of image quality. - ** Zooming lens **: The focal length can be adjusted, like the 24 - 70mm F2.8 zooming lens. The zoom lens was more flexible to use and could adjust the focal length within a certain range to meet different shooting needs. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to choose the focal length of the home surveillance camera?
When choosing the focal length of the home surveillance camera, you can refer to the following points: 1. ** Surveillance Scene * - ** Narrow space (such as garage, storage room, etc., the best monitoring distance is within 3 meters)**: You can choose 2.8mm focal length to obtain a larger field of view and a larger monitoring range. - ** Home or small shop (optimal monitoring distance 3 - 5m)**: 4mm focal length is more suitable, wider field of view, can capture a large range of scenery, can meet the basic monitoring needs, but the picture clarity and detail display ability is average, may need a higher resolution to make up for. - ** Family courtyard, balcony, door (optimal monitoring distance 5 - 10m)**: It is recommended to choose a 6mm focal length. Its field of view and clarity are more balanced. It can provide a relatively wide field of view, and can ensure the clarity and details of the picture. The resolution requirement is also relatively moderate. - ** Open areas (such as parking lots, playgrounds, etc.)**: 4mm focal length can be used to monitor large areas, but it may not be enough in terms of image clarity and details. If you need to cover a wider area (such as parking lots, factory workshops, etc.), a 6 - 8mm focal length lens is also a good choice. If you want to monitor a very long distance (such as a parking space 30 meters away), you may need a camera with a focal length of more than 12 mm. 2. ** budget and technical requirements **: The price of high-resolution cameras is higher, and the requirements for storage and processing equipment are also higher. If the budget is limited or the technical conditions do not allow it, comprehensive consideration should be taken when selecting the focal length. For example, you cannot choose a focal length that requires too much resolution and cannot be met by your own equipment. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What focal length do you choose for surveillance cameras?
The choice of focal length of a home surveillance camera needed to consider factors such as the monitoring range and the usage scene. For situations where the monitoring range is small and the viewing angle is large, such as the living room of a family, small shops, etc., you can choose a surveillance camera with a smaller focal length, such as a 3.6mm or 4mm focal length camera. The viewing angle can reach 75°-90 °, and the effective monitoring distance can reach more than 5 meters, covering 40 - 80 square meters of space. If it was a small space such as a garage or storage room, it was recommended to choose a 2.8mm focal length, and the best monitoring distance was within 3 meters. In an indoor or small shop environment, a 4mm focal length can also be considered, and the best monitoring distance is 3 - 5m. For a large monitoring range (such as a space of more than 10m * 10m), you need to choose a surveillance camera with a larger focal length. However, due to the large focal length, the monitoring angle will become smaller. You may need to consider using a dome camera or installing multiple surveillance cameras to ensure complete coverage. For situations where the monitoring range was fixed but the distance was very far, such as monitoring a parking space 30 meters away, a large focal length camera of 12mm or more would be needed. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What kind of focal length lenses do I need to match for beginner photography?
For beginners, the following focal lengths were more suitable: - Super wide-angle lens (focal length below 24mm): It has a large visual range and is suitable for shooting buildings and landscapes. It can shoot a small space in a small space. - Standard wide-angle lens (24mm-28mm): Mainly used for shooting scenery. - General wide-angle lens (35mm): It is called the Humanistic Eye, suitable for taking cultural photos, and can better reflect the relationship between the subject and the background environment. - Standard lens (50mm): It is mostly used for shooting humanities and portraits. It has a perspective effect similar to the human eye and a good background blurring effect. - Portrait lens (85mm): It has a good background blurring effect, suitable for close-up shots, and can maintain an appropriate communication distance with the model. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
objective focal length
The focal length of an objective lens is an important factor in an optical system. There were many methods to measure the focal length of an objective lens. The fixed-focal length collimator method had a large measurement range and high accuracy. The relative error was generally less than 1%. It was a commonly used measurement method. In a telescope, the multiplying power was equal to the focal length of the objective lens divided by the focal length of the eyepieces. In terms of aperture, the F value was the ratio of the focal length of the objective lens (f) to the perimeter of the entrance pupil (D). Different types of telescopes or instruments had different focal length values of the objective lens. For example, the focal length of an astronomical telescope was 400mm, and the focal length of the objective lens of the ZWJ - 851 Collimator was 200mm. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
On the application of focal length
In the field of photography, focal length was widely used. When shooting portraits, different focal lengths would produce different effects. For example, a focal length of 85mm was a better choice for close-up portraits, which could show a more natural facial features ratio. When shooting close-up portraits with a focal length of 17mm (a wide-angle focal length), the parts close to the lens such as the mouth, nose, and arms would be magnified, easily deformed, and the ratio of the character to the background would be exaggerated. As the focal length increased, the ratio of the character to the background would become more natural, the distance between the five facial features would be shortened, and the face would become flatter. The hairstyle would look thicker, and the face would not be so sharp. For the lens label, if the focal length label on the lens had two numbers (such as 17 - 40mm), it meant that it was a zoom lens, covering the focal length from 17mm to 40mm; if there was only one number (such as 50mm), it was a fixed-focus lens. The smaller the number, the shorter the focal length, the wider the angle of view, and the wider the viewing range. The picture could accommodate more elements but the proportion of each element was small. The larger the number, the longer the focal length, the narrower the angle of view, and the narrower the viewing range. The picture could accommodate fewer elements but the proportion of each element was larger. In some simple self-made microscopes (such as the glue stick microscope with an adjusted focal length), the focal length needed to be adjusted to observe the object (such as garlic film). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Calculating the Magnification of Industrial Lenses
In industrial lenses, optical magnification usually refers to the vertical axis magnification, which is the ratio of the size of the image to the object. The calculation method is: optical magnification = y'/y = camera chip size/field of view. For example, the known camera chip was 2/3 inches (8.8mm*6.6mm), and the field of view was 10mm * 8mm. If the long side is used for calculation, the magnifying power = 8.8mm/10mm = 0.88x; if the short side is used for calculation, the magnifying power = 6.6mm/8mm = 0.825x; at this time, the smaller magnifying power of 0.825x should be used as the optical magnifying power of the lens to be selected. Otherwise, the short-side field of view cannot meet the requirements (if 0.88x is used, the short-side field of view = 6.6mm/0.88x = 7.5mm<8mm). In actual projects, if the field of view was close to a square or a circle, the short side would be used for calculation; if the field of view was a long strip, the long side would be used for calculation. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What is the best focal length lens for human photography?
For cultural photography, 35mm and 50mm focal lengths were the better choices. The 35mm lens was the focal length that news photography loved to use in the film era. It was also known as the eye of humanity. It was a small wide-angle lens that could capture the environment of the person's movements better when shooting. It was not as exaggerated as the 24-point wide-angle lens, nor was it as flat as the 50-point fixed-focus lens. In the creation of documentary street photography, the wide angle of view could be used to integrate more elements into the picture and improve the atmosphere of the picture. Even if the aperture was fully open, there would be a relatively wide depth of field to record the background, which would bring more storytelling to the subject. The perspective effect of the 50mm focal length lens was the closest to human vision, and the image was plain and natural. Communication was smoother when the shooting distance was about 1 meter. In scenes such as street shooting, it allowed the photographer to maintain a certain distance from the subject and improve the success rate of shooting. Moreover, the focal length lens could provide a certain blurring effect. It could use the shallow depth of field to highlight the theme of the picture. It also achieved a higher resolution and could provide sharp details in the entire picture. Relatively speaking, the 85mm focal length was not suitable for cultural photography because of its narrow field of view and low environmental recognition. It did not meet the requirements of cultural photography to reflect the environment of people's activities. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Normal focal length of glasses
Normal glasses included short-sighted glasses and far-sighted glasses (presbyopic glasses). The focal length was related to the degree of the glasses. For short-sighted glasses, the degree and focal length were in an inverse relationship, that is, the shorter the focal length, the higher the degree. For long-sighted glasses (presbyopic glasses), the degree of the concave lens (far-sighted lens) was positive, and there was a similar relationship between the degree and focal length. To be specific, the power of the lens was equal to 100 divided by the focal length (in meters). For example, a 100-degree spectacles would have a focal length of 1 meter. However, it was not clear whether "normal glasses" were short-sighted or farsighted, so it was impossible to determine a specific focal length value. This was because different degrees of glasses had different focal lengths. From correcting mild vision problems to high vision problems, the focal length would vary greatly. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>