The shape and interface of the monitoring lens, as well as whether it is a fixed focus or zoom lens, or whether it supports automatic focusing. Does the small lens of the monitoring camera contain university questions?
Fixed focus and zoom
With different monitoring hosts, the lens can be divided into fixed focus and zoom. The biggest difference is to observe whether there are two rotatable screws on the lens. In terms of price, zoom lens is certainly more expensive than fixed focus lens at the same level; In terms of demand, or according to the actual application conditions of users, it is not necessarily better for zoom lens than fixed focus. If the surveillance camera is fixed, who will always adjust the lens?
Ordinary gun surveillance cameras are equipped with the most conventional lenses. Generally, fixed focus lens is selected for analog surveillance cameras, while some network surveillance cameras can be used with zoom lens. The focal length can be changed according to the actual demand.
Monitoring lens shape
If it is necessary to distinguish the shape of the monitoring lens, it is recommended to see whether the focal length can be adjusted, that is, the two screw knobs on the lens. Generally, the knob near the top of the lens adjusts the focal length. The mainstream zoom focal length is 2.8mm ~ 8mm, and the zoom focal length span of the high-end monitoring camera is large. The knob near the lens interface is used for focusing. When the focal length changes, the focus can be adjusted to the best position in time to capture the image.
In addition, even the zoom lens still has many differences in details, which mainly depends on the monitoring host. Some surveillance cameras support the auto focus function, so there will be a line connected to the fuselage on the monitoring lens, and some zoom lenses completely rely on manual adjustment. The same functions and different lenses have different meanings in appearance.
Dispute over monitoring lens interface
In addition to the differences in functions and appearance such as fixed focus, zoom and auto focus, consumers are more defeated in details. What is the difference between the interface of the monitoring lens?
In view of the dispute over the interface of monitoring lens, the C-type interface and CS type interface are mainly used in the market at present. The mainstream surveillance cameras are mainly CS circle. In terms of data analysis, the principle of distinguishing lenses of different interfaces is judged by the distance from the lens to the photosensitive surface: the distance from the mounting point to the focus of type C interface is 17.5mm, while the focus distance of type CS interface from the mounting point is 12.5mm, which is “shorter” compared with the former.
If there are different interfaces for surveillance cameras, there will be different types of surveillance cameras. In principle, it is not recommended to mix and match between C-type camera and CS type camera. In order to solve the problems in practical application, a 5mm C / CS adapter ring is added between C-lens and CS camera. However, the CS lens cannot be used with the C-type camera.
The monitoring lens is the main part of the monitoring camera. Although it is very common, it can not be ignored. After all, only when each accessory of the monitoring system reaches the best, can it combine the most perfect and clear video image and give full play to the best effect of the monitoring system.
Responsible editor: CT