What Is a Variofocal Lens?
The Zoom Settings and Focus According to the System Needs
Depending on the situation and the focused object that we want to make video surveillance, we also need to choose the type of camera lens as well.
There are two types of lenses in video surveillance cameras – fixed and varifocal lenses. In this article, we will discuss the question "What is a varifocal lens?" and what are its advantages.
The varifocal lens allows us to make an additional adjustment of the focus and the zoom.
Dahua cameras have two types of varifocal lenses – hand-held and motorized. Hand-held lenses can set on the camera side, as the name implies, with one hand. Cameras with motorized lens allows adjustment of focus and zoom through the recorder’s menu that makes them more easier to use and preferred by the installers. Another advantage of the motorized lens, if you decide to change the situation, is that the adjustment doesn’t cost time, nor effort.
What are the applications of the cameras with a varifocal lens?
Without doubt, they can’t be listed, but we will give a few examples to become more clear. The most common application is when the field under our surveillance applies a camera installation at distance of more than 5-10 meters. As an example we can point entrance/gate, which will supervise and it’s necessary to see details on entering or leaving cars. In the case that the camera cannot be mounted very close to the gate, it requires the use of such a varifocal lens. So even mounted at distance of 10-15 meters, we can adjust the zoom and the focus of our picture in a way that we need.
We have often clients who are looking for options to protect their own car, due to more frequent vandalism. If the customer lives on 3-4 floor and the car is parked 10-12 meters from the block, he can safely use camera with varifocal lens.
The varifocal cameras are often used for objects that has need of perimeter security, i.e. monitoring of unauthorized access to the property. Some of them include schools, farm buildings and yards, storerooms, trade warehouses.