1. Lens Focal Length: When considering the lens index, the plan designer needs to comprehensively consider the location of the monitoring target, the distance, the CCD specification, and the image effect of the monitoring target on the monitor, so as to select the lens with the most appropriate focal length. . For example, production line monitoring generally requires the monitoring of relatively close objects, and it requires a high level of definition. In this case, the fixed focus lens is generally better than the zoom, so the short focal length fixed lens is usually selected. Such as 2.8mm, 4mm, 6mm, 8mm and so on.
Another example is when monitoring indoor targets, the selected focal length will not be too large, generally will choose short focal length manual zoom lens, such as 3.0-8.2mm, 2.7-12.5mm; road monitoring, multi-lane monitoring to use shorter focal length , Such as 6-15mm; crossroads of the traffic light license plate monitoring to use a correspondingly longer focal length, such as 6-60mm; city security monitoring generally use a focal length longer power zoom lens, such as 6-60mm, 8-80mm , 7.5-120mm, etc.; highways, railways, rivers, environmental testing, forest fire prevention, airports, borders and sea defense, etc., generally need to use a variable focal length power zoom lens, such as 10-220mm, 13-280mm, 10- 330mm, 15-500mm and 10-1100mm.
2. Field of view angle range: There is a formula for the calculation of the field of view angle range. Knowing the focal length of the lens, the size of the CCD, and the angle of view can be calculated. The lens has such a rule: the larger the focal length, the farther the monitoring is, the smaller the angle of view is; the smaller the focal length, the closer the monitoring distance, the larger the angle of view, and the inverse relationship between the focal length and the angle of view. For example, in some projects with a manual zoom lens, the field of view angle range is the first to be considered, so the selected focal length range is generally determined based on the angle of view field. The power zoom lens can control the zoom and focus by the keyboard at any time according to the scene environment, so the angle of field of view is not too much to consider. However, when the starting focal length of the power zoom lens is too large (for example, the initial focal length exceeds 20 mm), a wide range of monitoring cannot be achieved.
3. The aperture of the lens: The amount of light passing through the lens is measured by the ratio of the focal length of the lens to the clear aperture (F=f/D), denoted by F. Each lens is marked with its maximum F-number, the smaller the F-number, the larger the aperture. For constant lighting conditions, fixed aperture lens can be used, this is generally a laboratory environment; for the environment where the illumination intensity is not obvious, manual iris lens is often used, that is, after the aperture is adjusted to a more ideal value, it can be fixed. If the illuminance changes greatly, 24-hour all-weather outdoor monitoring is required. The auto iris lens should be used.
The application location of the monitoring lens fixed aperture lens: fixed focus and fixed aperture, mainly used for ambient light fixed place;
Manual iris lens: fixed focus but adjustable aperture, mainly used for fixed ambient light but indefinite place;
Auto iris lens: fixed focal length, using a DC voltage to drive a fixed-range location for ambient light variability;
Auto-iris lens: fixed focal length, using a video signal to drive a fixed-range location for ambient light variability;
Manual iris zoom lens: It is mainly used in indoor environment where the degree of light is variable and the range is not the same;
Automatic aperture zoom lens: It is mainly used in outdoor environment where the ambient light is variable and the range is not the same;
On-Board Lens (on-Board): mainly with infrared cameras, both indoor and outdoor;
Fish-eye panoramic lens: It is mainly used in indoor environment where the degree of light is indefinite and the size of the range is specific;
Electric zoom lens: It can remotely control the depth of focus and aperture of the focal length. It is mainly used in places where the indoor and outdoor ambient light levels are not constant and the depth of field range can be adjusted according to requirements;
Pin-Hole: Mainly used for concealed monitoring and ambient light with a range of specific places.
Another example is when monitoring indoor targets, the selected focal length will not be too large, generally will choose short focal length manual zoom lens, such as 3.0-8.2mm, 2.7-12.5mm; road monitoring, multi-lane monitoring to use shorter focal length , Such as 6-15mm; crossroads of the traffic light license plate monitoring to use a correspondingly longer focal length, such as 6-60mm; city security monitoring generally use a focal length longer power zoom lens, such as 6-60mm, 8-80mm , 7.5-120mm, etc.; highways, railways, rivers, environmental testing, forest fire prevention, airports, borders and sea defense, etc., generally need to use a variable focal length power zoom lens, such as 10-220mm, 13-280mm, 10- 330mm, 15-500mm and 10-1100mm.
2. Field of view angle range: There is a formula for the calculation of the field of view angle range. Knowing the focal length of the lens, the size of the CCD, and the angle of view can be calculated. The lens has such a rule: the larger the focal length, the farther the monitoring is, the smaller the angle of view is; the smaller the focal length, the closer the monitoring distance, the larger the angle of view, and the inverse relationship between the focal length and the angle of view. For example, in some projects with a manual zoom lens, the field of view angle range is the first to be considered, so the selected focal length range is generally determined based on the angle of view field. The power zoom lens can control the zoom and focus by the keyboard at any time according to the scene environment, so the angle of field of view is not too much to consider. However, when the starting focal length of the power zoom lens is too large (for example, the initial focal length exceeds 20 mm), a wide range of monitoring cannot be achieved.
3. The aperture of the lens: The amount of light passing through the lens is measured by the ratio of the focal length of the lens to the clear aperture (F=f/D), denoted by F. Each lens is marked with its maximum F-number, the smaller the F-number, the larger the aperture. For constant lighting conditions, fixed aperture lens can be used, this is generally a laboratory environment; for the environment where the illumination intensity is not obvious, manual iris lens is often used, that is, after the aperture is adjusted to a more ideal value, it can be fixed. If the illuminance changes greatly, 24-hour all-weather outdoor monitoring is required. The auto iris lens should be used.
The application location of the monitoring lens fixed aperture lens: fixed focus and fixed aperture, mainly used for ambient light fixed place;
Manual iris lens: fixed focus but adjustable aperture, mainly used for fixed ambient light but indefinite place;
Auto iris lens: fixed focal length, using a DC voltage to drive a fixed-range location for ambient light variability;
Auto-iris lens: fixed focal length, using a video signal to drive a fixed-range location for ambient light variability;
Manual iris zoom lens: It is mainly used in indoor environment where the degree of light is variable and the range is not the same;
Automatic aperture zoom lens: It is mainly used in outdoor environment where the ambient light is variable and the range is not the same;
On-Board Lens (on-Board): mainly with infrared cameras, both indoor and outdoor;
Fish-eye panoramic lens: It is mainly used in indoor environment where the degree of light is indefinite and the size of the range is specific;
Electric zoom lens: It can remotely control the depth of focus and aperture of the focal length. It is mainly used in places where the indoor and outdoor ambient light levels are not constant and the depth of field range can be adjusted according to requirements;
Pin-Hole: Mainly used for concealed monitoring and ambient light with a range of specific places.
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