The hood of an optical lens
The hood was a device installed at the front of the camera lens, digital camera, and video camera. It was an important part of the lens optical system. Its main uses included: 1. ** Suppression of stray light **: avoid glare and improve image clarity and color reproduction. In different light positions such as backlighting, side backlighting, forward lighting, side lighting, lighting photography or night photography, it can prevent non-imaging light, surrounding scattered light or interference light from entering the lens, avoid fog and halo phenomena, and improve the color saturation and clarity of the picture. 2. ** Protect the lens **: When the lens is accidentally dropped, it can help reduce the damage caused by the fall; it can prevent fingers from accidentally touching the surface of the lens; it can also block the sand, rain, snow, etc. to a certain extent to prevent other things from directly touching the surface of the lens. In terms of usage, the hood in front of all the lenses had been carefully calculated by the manufacturer to help improve the quality of the shot. If the lens was equipped with a crystallizer, although the crystallizer and the hood had no similarities, the hood still needed to be installed. When rotating the crystallizer, the hood could be turned upside down and buckled on the lens, or temporarily removed and placed in the camera bag. It was not necessary to buy the original hood. Buying a hood that matched the lens 'caliber and angle of view could play its role. Read more exciting novels for free
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>
Classic lens optical structure
The following are the optical structures of some classic lenses: 1. Single-piece lens (one set, one piece): It was first invented by the Englishman Wollaston in 1812. It had a maximum aperture of F16 and was called a crescent-shaped landscape lens. Its structure could not change the aperture. It was mostly used in early simple box-type cameras (mainly for artists to draw pictures). This structure was similar to the structure of the human eye, but because the camera lens only had one lens, the image would have problems such as spherical aberrations, color aberrations, and coma. Lenses with this structure were commonly seen in presbyopic glasses, but strictly speaking, presbyopic glasses could not be called lenses. 2. **1 set of 2 lens structure **: invented by the Frenchman Chevalier in 1821. It was an achromatic lens with a maximum aperture of F14. It was also a lens with a non-changeable aperture. It glued the concave lens and the concave lens together to eliminate some of the color aberrations. In 1839, the Kilux camera invented by Daguerre used this kind of lens. 3. ** Petzval structure (3 sets of 4 pieces)**: In 1840, the Austrian mathematician Professor Petzval used mathematical methods to design a portrait lens with a maximum aperture of F3.7. This structure of the lens is still popular today. 4. ** Double Gauss structure **: It appeared during World War II. 5. [Heavenly Sai structure: 100 years of history.] <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>
Gyron optical fiber cleaning lens
If you want to clean the lens of the Geelong optical fiber fusion splicer, you must first turn off the fusion splicer, remove the front and back covers of the pole, and then use a cotton swab dipped in high-quality alcohol with a purity of more than 99%. Starting from the center of the lens, make the cotton swab move in a spiral shape until the edge of the lens surface to gently clean the lens surface. Finally, use a dry cotton swab to remove excess alcohol. During the operation, be careful not to bend the pole. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Production and testing process of optical lens
Sunny optical phone lens design
Sunny Optics 'phone lens design had many features. The lens was known for its high definition and optimized optical design. For example, the slanted lens design improved the shooting performance in low-light environments. At the same time, Shunyu introduced advanced coating technology in its latest lens, which reduced reflection and significantly improved color reproduction, allowing users to feel more realistic colors and higher contrast. In addition, the lens also adopted a lightweight design, allowing smartphone manufacturers to retain a smaller body while providing more powerful shooting capabilities. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Promotion of optical lens to related industries
The optical lens had a significant role in promoting many related industries: ** I. Photographic and Video Industry ** 1. ** Image quality improved ** - In the field of photography and video, high-quality optical lenses were the key to producing high-quality images. The optical characteristics of the lens, such as focal length, aperture, angle of view, and aberrations, directly determined the quality of the image. Different types of lenses were suitable for different shooting scenes. For example, wide-angle lenses were suitable for shooting scenery, while telephoto lenses were suitable for close-up or long-distance objects. - For professional film production, advertisement shooting, and photography art creation, high-quality optical lenses could capture more details, make the colors more realistic, and have higher contrast, thereby enhancing the artistic and commercial value of the work. 2. ** Drive technological innovation ** - With the development of optical lens technology, new technologies such as zooming lenses and autofocus lenses made photography and video equipment more convenient and versatile. For example, the appearance of autofocus lenses greatly improved the efficiency and accuracy of shooting, allowing photographers to focus more on composition and creative expression. ** 2. Scientific Research ** 1. ** Microscopic observation ** - In microscopic fields such as cell research, optical lenses were used in microscopes. High-resolution optical lenses could magnify tiny cell structures, allowing scientists to observe microscopic phenomena such as organelle and cell division inside cells. This was crucial for research in biology, medicine, and other disciplines. 2. ** macro observation ** - In the field of astronomical observation, the optical lens in the telescope could collect the light of distant celestial bodies and form an image. Large-caliber, high-precision optical lenses could allow astronomy to observe more distant galaxies, star formation, and other astronomical phenomena, contributing to the development of astronomy. - In materials science research, optical lenses could be used to observe the microscopic structure and surface shape of materials, helping scientists analyze the properties and characteristics of materials and promote the development of new materials. ** 3. Photolocation Industry ** 1. ** Key to chip manufacturing ** - In the field of photolithographic, optical lenses were key components in the manufacture of integrated circuits. Photolocation technology was the key process to transfer circuit patterns onto the chip, and the quality of the optical lens directly affected the performance and reliability of the chip. - High-precision optical lenses could achieve smaller photolithographic resolution, which could produce size and higher-performance chips. This was crucial to the development of the semiconductor industry, such as increasing the computing speed of computer processors and reducing the power consumption of electronic devices. ** 4. Eyewear industry ** 1. ** Vision correction and protection ** - For the glasses industry, the development of optical lenses made the functions of glasses constantly improve. Whether it was short-sightedness, farsightedness, or refraction, suitable optical lenses could accurately correct vision. - At the same time, optical lens technology was also applied to the manufacture of protective glasses such as sunglasses, such as the development of functional lenses such as anti-violet and anti-blue light to provide better protection for people's eyes. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Does the smartphone lens have optical zooming?
The smartphone lens had an optical zooming function. The optical zooming effect was achieved by moving the lens position. The photo taken after zooming was clearer and could be compared to a telescope. However, due to the limitations of technology and the internal space of the phone, the highest optical zoom factor of most mobile phones was 5 times, and only a few models could reach 10 times optical zoom. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Puyi optical
Puyi Eyewear was a high-end eyewear brand founded in Hong Kong. Its price was higher because it was of very high quality, and the materials and craftsmanship used were very exquisite. Pu Yi glasses were designed, produced, and sold by brand manufacturers, so the price was much more expensive than ordinary glasses. Pu Yi Glasses cooperated with many internationally renowned brands to provide high-quality products and services, as well as a luxurious experience. Its stores provided a personalised service, selecting matching styles for each customer, and providing a series of shopping experiences and VIP services. Mr. Qiu Zijie, the founder of Puyi Glasses, shared his experience and ideas in brand management, product selection, and service content. Pu Yi Glasses was based on the personalisation and advanced optometrification and eye protection technology, providing perfect answers for every pair of eyes. Puyi Glasses had been in the market for 18 years and had become the leader of the luxury glasses market.
camera optical parameters
The optical parameters of the camera included the following aspects: 1. ** focal length **: This is a very important optical parameters of the lens. It refers to the distance from the main point of the lens to the focal point. It is an important performance indicator of the lens. The length of the focal length of the lens was inverse to the size of the image taken by the lens. That is, under the same object distance, the larger the focal length of the lens, the smaller the size of the image taken. Most industrial cameras use fixed-focus lenses in practical applications. Before choosing the focal length of the lens, you need to know the object distance of the on-site camera (the installation height of the camera lens from the surface of the measured object) and the field of view of the camera (the size of the characteristics of the measured object). In some applications involving the mixed inspection of objects at different heights, the use of a variable focal length lens would be considered. However, the variable focal length lens had two issues to consider: zooming speed and lens life. 2. ** Depth-of-field **: When the focal length of the lens is adjusted to a focal point, only the objects within a certain distance before and after the focal point are clearly visible. The objects outside this distance are blurred. This distance is the depth of field of the lens. 3. ** Pieces and resolution **: Pieces are the smallest unit of an image generated by the imaging chip, such as a 2-million-pel image. The resolution referred to the imaging ability of the CCD-or CMOS-chip. For example, the resolution of a 2-million-pel camera was 1626 x 1236, which meant that the camera had 1626 x 1236 rows in the X-axis direction. The total image taken was about 2 million pel. The detection accuracy could be simply evaluated by dividing the actual size of the image's X-axis by the number of X-axis dots. However, the final detection accuracy was affected by many factors, including the moving speed of the object being measured, light interference, the shape of the object, the contrast of the features, the computing power of the software, and so on. 4. ** Picture element size **: This is also an important optical parameters of the camera. 5. ** Target size of sensor **: It is the most concerned part of the camera's optical parameters. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>