Why is Focal Lens important?
If you’re looking for a security camera for the office or warehouse and you want to see as much as you can, you should look for a 2.8 or 4mm lens (provides a wide, somewhat distant view). If you need to observe a limited area, such as an entrance, you should choose an 8mm lense (provides a narrow view and objects are closer). In other words, the smaller the focal length number, the wider the field of view. To get the most flexibility in choosing the best field of view, consider a varifocal lens.
