About Lens

Which Lens Should I Select?
One of the difficult problems when setting up a CCTV system,
is choosing the right lens for yours cameras as different lenses give different fields of views, and different levels of zoom.

As a guide:
‧The smaller the focal length number (ie 2.8mm)= the wider the field of view
‧The bigger the focal length number (eg 12mm)= the narrow the field of view

If you have security camera in the office or home and you want to see as much as you can,
you should go for 2.8 or 3.6mm lens (makes a wider view).
If you want to observe a limited area, like an entrance you should go for 6mm or 12mm
(makes a narroe view and objects are closer).

If you are not sure of which lens, then choose a vari-focal lens camera (ie 2.8mm-12mm manual)
so you can adjust the view once the camera is mounted into position.

The following images are designed to be a guide to assist you in selecting a camera lens size for yours
installation/application.


A 2.8mm lens gives around 105 degrees viewing angle.
 A 3.6mm lens is designed to provide an approximate 84 degrees field of view

2.8mm
Offers a wider field of view, and is typically the broadest field of view for most standard CCTV Cameras.

3.6mm
3.6mm is a legacy camera size. It offers a relatively wide, but slightly more zoomed in field of vision.

the more narrower the lens, the focus is further away. Eg. typical 3.6mm lens is focus 4-10 metres.
typically 2.8mm is 1-6 metres. This means that for areas like the front door where you are capturing someone 1-4 metres away, 2.8mm is ideal.
Sides of homes, 3.6mm may be more ideal.