What is the difference between 2.8 mm, 4 mm, 6 mm and 8 mm lens?

Lens focal length tells us the angle of view—how much of the scene will be captured—and the magnification—how large individual elements will be. The lager the focal length, the narrower the angle of view and the higher the magnification.

 VIGI indoor cameras have a focal length of 2.8/4 mm and VIGI outdoor cameras have a focal length of 4/6 mm.  The last digit of the model indicates the focal length of the lens.

For example:

VIGI C400HP-4: The focal length is 4 mm.

VIGI C300HP-6: The focal length is 6 mm.

How to select suitable lens?

The larger the focal length of the lens, the smaller the angle of view, and the farther the monitoring distance.  So the camera lens with low focal length is suitable for observing small areas where need a wide angle. If you want to observe the objects closer with a big distance, you’d better select the cameras with a lager focal length lens.