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With the advancement of science and technology, certain specialized industries have specific requirements regarding surveillance. In occupational environments such as those in the chemical, petroleum, and coal industries, there is a risk of the presence of explosive gases or dust; therefore, it is essential to install explosion-proof cameras. Ensuring a safe working environment in industrial production is the primary purpose of explosion-proof surveillance cameras. Now, explosion-proof surveillance is becoming increasingly important in society. But what impact does the distance of explosion-proof surveillance cameras have? What factors are influenced by the distance of explosion-proof surveillance cameras? How should one choose the appropriate explosion-proof surveillance camera based on the distance? Next, Tongbang Explosion-Proof will explain: As a security technology, the explosion-proof camera CCTV system is playing an increasingly important role in places such as luxury hotels, banks, chemical plants, oil depots, ports, docks, and government agencies. Even modern petrochemical enterprises use CCTV systems as an important means for ensuring security and safe production. To enable security CCTV technology to play a better role in industrial safety production, it is crucial for both economic considerations and technical performance to choose the appropriate explosion-proof camera lenses in each CCTV monitoring project. Classification of lenses: Based on the application scenarios in surveillance settings, lenses can be roughly classified as follows: 1. Wide-angle lenses: With an angle of view of over 90 degrees, they are generally used in small laboratories, halls, and other areas where the viewing distance is short but the required angle of view is large; 2. Standard lenses: With an angle of view of around 30 degrees, they are typically used in corridors and along the perimeters of production areas; 3. Telephoto lenses: With an angle of view of less than 20 degrees, their focal length ranges from several dozen millimeters to over a hundred millimeters, and they are used for long-distance monitoring; 4. Zoom lenses: These lenses have a variable focal length, allowing them to switch from wide-angle to telephoto mode, and they are suitable for areas that require a large depth of field and a wide range of angles of view. Determining the focal length of a lens: When selecting a lens, five factors determine its specifications: (1) The size of the surveillance area; (2) The size of the object being monitored; (3) The object distance; (4) The focal length. Choice between manual and automatic apertures: Lens apertures can be either manual or automatic. In the past, due to the use of explosion-proof infrared cameras in outdoor areas or other special environments, automatic aperture lenses were more commonly used. In current surveillance projects, due to the widespread use of CCTV surveillance systems in industrial production, indoor surveillance locations account for a large proportion. And many engineering contractors also prefer to use auto-aperture lenses when quoting prices for engineering equipment. Although auto-aperture lenses are more adaptable to changes in light levels at monitoring locations, their price is also significantly higher than that of manual fixed-focus lenses with the same focal length. And nowadays, most explosion-proof cameras have electronic shutters, and the light sources indoors are also relatively stable. Therefore, there is little need to use automatic aperture lenses extensively in industrial monitoring projects; on the other hand, the automatic aperture lenses available on the market today fall into two main categories: a. power-driven automatic aperture lenses; b. video-driven automatic aperture lenses. Power-driven auto-aperture lenses are controlled by four wires: two of these are used for a DC12V or AC24V power supply to drive the motor inside the lens, while the other two control wires detect the intensity of external light using light sensors within the lens in order to adjust the aperture size. Video-driven auto-aperture lenses, on the other hand, are controlled by three wires: one of these serves as a video trigger signal to activate the aperture and control its size, while the other two are power wires providing DC12V or AC24V power to drive the motor. Most of the black-and-white or color explosion-proof cameras available on the market today have lens interfaces with automatic aperture functions, but aside from a few that can be compatible with both types of lenses, most explosion-proof cameras are not compatible; they can only use power-driven automatic aperture lenses or video-driven automatic aperture lenses. If some explosion-proof cameras get damaged during use, there is an issue of whether the newly purchased explosion-proof cameras are compatible with the original auto-aperture lenses. However, when the monitoring points in a project are located outdoors, it is necessary to use lenses with automatic apertures, as the dynamic range of light outdoors varies greatly – the ambient illuminance can reach 50,000 Lx to 100,000 Lx under summer sunlight, while it is only 10 Lx under street lighting at night, showing a significant variation. Under such circumstances, whether the vehicle-mounted explosion-proof camera has an automatic sensitivity adjustment function or not, it is impossible for the electronic shutter built into the camera itself to adapt to such a wide range of illuminance levels, and thus it cannot achieve the desired control over the image quality. In a television surveillance system, it is very important to select the appropriate explosion-proof surveillance camera lenses based on the environment being monitored. This is because it directly affects the quality of the image displayed on the monitors at the end of the system, in terms of both the range of the view and the details of the image. By choosing the right explosion-proof fixed-lens cameras, the system can be optimized for optimal performance, resulting in satisfactory surveillance results. In terms of aperture, explosion-proof zoom camera lenses can be divided into manual-aperture lenses and auto-aperture lenses; in terms of focal length, they can be divided into fixed-focus lenses and zoom lenses. The above analysis details the impact of distance on explosion-proof surveillance cameras; please use it as a reference.