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The selection of lens millimeters, sensor size and other factors are important aspects affecting the shooting angle.
Let us first take the JVS-N81-HY-S (1/2.7′′ CMOS) as an example to illustrate the relationship between the number of millimeters of the lens and the distance and angle. See the figure below: 
However, on the premise of the same number of millimeters, if the sensor size is different, the viewing angle is different. The products of different brands have the same viewing angle with the same number of millimeters and the same sensor size. Therefore, it is necessary to determine the monitoring perspective. Consider multiple factors together. The angle of view is the angle that can be taken in the specified image field, usually refers to the angle when the lens is at infinity. The same focal length, if the field size is different, the viewing angle is different. In addition, there are other factors such as resolution, pixel size, etc. that affect the viewing angle.
At present, to obtain a more accurate perspective, the following formula is usually used for calculation: 
In addition, the objective factors such as the location of the camera installation will also affect the shooting distance and angle of the camera, and should be taken into account in the occasion of special precision needs. Because there is too much content, we will not go into details. We take China-Vietnam products as an example to recommend several products for different scenarios.
For example, in the monitoring of narrow spaces such as elevators, we recommend the use of the Zhongwei elevator dedicated machine: JVS-N73-DT. It is a super-wide-angle 2.8MM lens, the monitoring angle reached 115 degrees, can guarantee that there is no dead corner in the elevator. 
In indoor environments such as small shops and homes, IPC of a 4mm lens is recommended. The main consideration is that the indoor distance is not too far (3-6 meters), and the monitoring angle is large enough. 
In the outdoor road, the same scene of Hu, you can choose 6MM or 8MM camera, especially recommended in the peacekeeping 200W camera, with a corridor mode, so that the picture is more perfect. 
The 12MM lens is mainly used to monitor a specific location, such as some equipment and equipment, entrances and exits. 
What if you don't know how many millimeters are most suitable? It does not matter, we also have a dedicated JVS-N71-ZOOM, you can manually adjust the lens millimeters. 
If you are not satisfied, please order the Zhongwei dome camera and try a 1080P/20x optical zoom HD dome camera.
- Details of the license plate 180 meters away, character characteristics 200 meters away, contours of objects 300 meters away! 
How to choose IPC
Customers often ask: Why did you buy a well-known IPC, or can't see the distant picture? This involves the issue of the shooting angle that you need.
(Note: There will be differences between different brands and models, and the overall trend is the same)
The smaller the camera lens millimeter, then the greater the angle of the monitor screen, but the closer the clearest distance; conversely, the larger the lens millimeter of the camera, the smaller the angle of the monitor screen, but the clearest distance The farther away.