Understanding security camera lenses enough to decide which is best for your surveillance security camera needs can be a confusing and overwhelming process. Lens descriptions such as fixed-lens, 2.8mm, 4mm, 6mm, 12mm or vari-focal lens doesn’t really give you the information you need unless you’re already a camera expert. The numbers listed with the security camera lens may seem simple enough, it is far more confusing to know the implications behind those numbers.
To choose the right security camera lens, it is important to gain an insight into the CCTV camera lens types..
Types of CCTV Security Camera Lens
In a nutshell, CCTV security camera lenses contain either a fixed lens (also called monofocal lens) or varifocal lens.
A fixed lens camera’s focal length (2.8mm, 4mm, etc) is fixed or permanently set, meaning that the field of view’s focal length cannot be changed or adjusted without using a different camera.
In contrast, a varifocal lens allows you to adjust the camera’s focal length for your specific needs but are typically more expensive than fixed lens camera.
TIP: The most common type for general use in residential and commercial systems are fixed-lens with a focal length of 2.8mm, 3.6mm or 4mm.
Some varifocal lens security cameras have manual focal length adjustments on the camera itself but many are equipped with motorized zoom lenses, such as PTZ security cameras, that can be controlled remotely via an app, web interface or CCTV joystick.
Suggestion: If you need to switch easily between wide angle lens and narrow field of view, choose a security camera with a zoom lens. The camera’s field of view can be remotely controlled through Zoom/Focus buttons on the app, web interface or a CCTV joystick.
Example Focal Length/Field of View Comparisons
Notice how the 2.8mm lens shows a lot more area but the taxi among other things are further away. Each increase in focal length is more narrow but everything is more zoomed in (or closer appearing).