Wide-angle lenses

Why do images presented by a lens have optical aberrations?A. DistortionDistortion will cause real objects to be straight lines, but in photos to be non-straight lines, to be curved lines.a) barrelb) pincushionc) complex/wavyTypes of lenses prone to distortion: usually zoom lenses and wide-angle lenses.B. Field curvatureFor plane objects in reality, after imaging, the real image surface is curved, and most actual sensors are also flat, which will cause the center field of view and the edge field of view to be unable to present clear images at the same time.Lens types prone to field curvature: usually wide-angle lenses and large aperture lenses.C. Vignettinga) Vignetting-----Light FalloffUneven brightness Light Falloff, the exposure of the center field of view and the edge field of view are different, resulting in inconsistent brightness between the center and edge of the picture, which is what we often call the camera vignetting problem.b) Vignetting-----Color CastUsually there is a color difference between the edges of the picture (especially the corners) and the center area. It is not entirely caused by lens aberration, filters and sensors will also have a certain impact.Types of lenses prone to vignetting: usually largeThere are many factors that cause optical aberration in lenses, some of which have been shared above:1) distortion2) field curvature3) Vignetting ---Light Falloff4) Vignetting ---Color CastIn fact, there are some other influencing factors:1) Focus ShiftWhen you reduce the aperture size, the best focus plane will move to the front or back. That is, the aperture size will affect the best focus plane position, which is what we call focus shift.Common lenses that are prone to focus shift: large aperture lenses. When adjusting the aperture, the focus usually needs to be re-adjusted.2) Onion ring bokehThere are some out-of-focus circular rays of light in the optical path of the lens, which is generally caused by a defective lens.Common lenses that are prone to "onionrings": Some large aperture lenses often use aspherical lenses because of the flatness of the surface involved during processing.3) Flare-GhostingWhen there are some abnormal colored patches in the presented image, usually like colored circles or colored blocks of specific shapes, we become ghost images.Common ghost images: zoom lenses, lenses with a large number of lenses, and large-diameter lenses. During processing, try to reduce the aperture as much as possible, or use post-image processing.4) Flare-Internal ReflectionsGenerally speaking, highly reflective objects inside the lens, such as structural parts with too high reflectivity, or dirty lenses in the optical path, etc. In most cases it is caused by workmanship issues.Common internal reflection stray light lenses:especially large aperture lenses, during the production process, you can try to eliminate light, cut off light, block stray light, increase transmittance, and reduce the aperture as much as possible when conditions permit.

A cost-effective tachograph is essential for providing evidence of vehicle safety and insurance claims. Here are some ways to purchase a tachograph: Good video recording: Choose a dashcam with high resolution, at least 1080p full high definition resolution or better. High resolution dashcams can capture a lot of details, such as traffic signs, traffic lights, pedestrians, license plate numbers, etc. In the event of an accident or dispute, these records can be used as evidence to prove innocence and to support insurance claims. Wide viewing angle: The basic shooting angles are: 90 degrees, 100 degrees, 120 degrees, 140 degrees, 150 degrees, 170 degrees, etc. The more popular single-lens driving recorders are equipped with wide-angle lenses of 120 degrees or 140 degrees. When a single lens is 170 degrees, the picture will be seriously deformed, affecting the clarity of the picture. If you choose a driving recorder with a wide-angle lens, it is recommended that buyers use a viewing angle of at least 130 degrees to ensure a wider field of view is recorded. Night use: It is necessary to pay attention to the performance of the driving recorder at night or in low-light conditions. The driving recorder has a night vision lens that can capture the faint light that the human eye cannot detect and magnify it, allowing you to see objects and scenes in extremely dark environments. Storage capacity and loop recording: Driving recorders typically use a memory card to save recordings. Choose to have enough storage capacity to record as long as you need, while supporting loop recording to automatically overwrite old recordings when the memory card is full. G-sensor: The G-sensor can sense the force of a collision or sudden change, saving the relevant video footage as an emergency to prevent it from being overwritten by loops. Vehicle power and parking monitoring: Some tachographs have the ability to connect to the vehicle's power supply, which can automatically start recording in the event of an incident. In addition, some tachographs also have parking monitoring capabilities, which can record while the vehicle is parked.Car rearview lens can help car owners achieve the desired parking effect Convenience and versatility: Consider choosing a dashcam that is easy to use and set up. Other features include GPS recording, Wi-Fi connectivity, mobile app control, and more. Brand and user reviews: Select well-known brands and review the reviews and opinions of other users to understand the reliability, after-sales services and performance of the dashcam. Legal requirements: Understand the legal requirements and regulations in your area and ensure that the selected driving recorder complies with local regulations. 3C certification: At present, buses, buses and school buses need to install tachographs, logistics and transportation companies have also begun to install tachographs, and require products to be 3C certified. According to the tachographs regulations of the National Compulsory Certification Quality Center, tachographs and car black boxes must be 3C certified before they can be sold. Therefore, buyers should choose carefully when choosing products and buy products produced by regular manufacturers with 3C certification. Budget: Determine the scope of purchasing a tachograph according to your own budget, and make a trade-off between quality and functionality. Try to choose a well-concealed one to reduce the risk of window smashing and theft. Please note that these guidelines are for reference only, and buyers need to adjust them according to their individual needs and priorities, and carefully compare different brands and   models of dashcams before purchasing.

A wide-angle camera lens is a photographic lens with a focal length shorter than a standard lens, a viewing angle larger than a standard lens, a focal length longer than a fisheye lens, and a viewing angle smaller than a fisheye lens. A fisheye camera lens is a lens with a focal length of 16mm or less and a viewing angle close to or equal to 180 °. It is an extreme wide-angle lens, and "fisheye lens" is its common name. The difference between the two: Field of view: Fisheye lenses have a very wide field of view, usually more than 180 degrees, and can capture a very wide scene, or even show a fisheye effect, that is, the center of the image is stretched and the edges are curved. The field of view of wide-angle lenses is usually between 90 degrees and 120 degrees, and the captured scene is wider, but not as wide as fisheye lenses.   Perspective effect: The lens design and field of view of the fisheye lens are special, and the captured image will produce a curved perspective effect, making the object in the center of the image appear larger, and the object at the edge will be stretched to create a unique effect. The wide-angle lens can also capture a wide scene, but generally there will be no curved perspective effect.   Distortion effect: The fisheye lens has a very obvious distortion effect, the image shows a curved shape, the center part is relatively normal, but the edge part will be stretched and distorted. The distortion effect of the wide-angle lens is relatively small, and the shape of the image is closer to reality.   Focal length selection: Fisheye lenses usually have a very short focal length, often between 8mm and 16mm, which allows them to capture very wide scenes. The focal length of wide-angle lenses is relatively longer, generally between 20mm and 35mm, and some lenses even exceed 50mm.   Purpose: Application examples of wide-angle lenses: Landscape photography: A wide-angle lens can capture vast scenes such as vast skies, beautiful mountains, and magnificent beaches. It can help photographers incorporate more elements into the picture to create a broad landscape effect. Architectural photography: Wide-angle lenses can capture the general outline and texture of a building, making it look grander and larger. It allows photographers to capture entire buildings in tight spaces, such as cathedrals, skyscrapers or narrow streets. Interior photography: In indoor environments, wide-angle lenses can capture more details, making them suitable for photographing interior design, museums, galleries, and other indoor venues. They can bring out the atmosphere and layout of the entire space. Vehicle cameras: They are usually installed in the front and rear parts of the car to increase the driver's field of view and improve safety. It can be turned into rear monitoring camera lenses, car reversing aid camera lenses, fatigue monitoring camera lenses, blind spot detection lenses, driving recorder camera lenses, driver security cameras lenses. Smart home: Wide-angle lens can be used for smart home security camera lens. Perform environmental awareness, real-time positioning and tracking, and enhance virtual reality experience.           b.Application examples of fisheye lenses: Photography and filmmaking: Fisheye lenses are often used in photography and filmmaking to capture a very wide range of scenery or scenes. They are widely used in sports events, travel documentaries, outdoor sports dv camera lenses and other fields to present unique and exaggerated visual effects. CCTV cameras: Fisheye lenses play an important role in traffic monitoring systems. Installed in areas such as intersections, parking lots or prisons, it can provide a full range of monitoring views, thus enhancing security and surveillance effects. Astronomy: Astronomers use fisheye lenses to observe the sky, especially for capturing images of the stars throughout the sky. These camera lenses capture a wide view of the sky and are useful for studying celestial bodies such as galaxies, planets, and nebulae. Scientific research and industrial applications: Fisheye lenses also play an important role in scientific research and industrial applications. For example, they are used in aerial surveillance, intelligent machine camera lens vision systems, drone camera lens navigation and other applications in the aerospace sector.