Elevator in the monitor camera lens focal length with the number
Usually 3.6 mm lens angle can cover the entire elevator, 2.8 mm wide range for more space for the elevator. The larger the number of millimeters, the narrower the angle of view, look farther
The smaller the number of millimeters, the greater the angle, see the closer .3.6 mm angle of about 75 degrees, the proposed monitoring distance of 5 meters .2.8 mm angle of about 90 degrees, the proposed monitoring distance of 3 meters
Elevator lens generally use wide-angle lens, commonly used wide-angle lens is 2.8 mm, 3.6 mm. Generally installed in the upper right corner of the elevator or the upper left corner of the location
