Vonnic Standalone DVR Uživatelský manuál stáhnout pdf (Strana 6)

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Lenses continued

Field of View Chart

If you know the distance from where your camera will be mounted to the area you want to

monitor, you can better determine what lens you need. If you want to monitor an area 30ft by

40ft and it is 50ft away, using the chart above, you can determine you will need a 6.0mm

lens.

5ft 10ft 25ft 50ft 100ft 200ft

2.8mm 6.4 x 8.6 12.9 x 17.1 32.1 x 42.9 64.3 x 85.7 128.6 x 171.4 257.2 x 342.8

4.0mm 4.5 x 6.0 9.0 x 12.0 22.5 x 30.0 45.0 x 60.0 90.0 x 120.0 180.0 x 240.0

6.0mm 3.0 x 4.0 6.0 x 8.0 15.0 x 20.0 30.0 x 40.0 60.0 x 80.0 120.0 x 160.0

8.0mm 2.3 x 3.0 4.5 x 6.0 11.3 x 15.0 22.5 x 30.0 45.0 x 60.0 90.0 x 120.0

12.0mm 1.5 x 2.0 3.0 x 4.0 7.5 x 10.0 15.0 x 20.0 30.0 x 40.0 60.0 x 80.0

25.0mm 0.7 x 1.0 1.4 x 1.9 3.6 x 4.8 7.2 x 9.6 14.4 x 19.2 28.9 x 38.4

50.mm 0.4 x 0.5 0.7 x 1.0 1.8 x 2.4 3.6 x 4.8 7.2 x 9.6 14.4 x 19.2

75mm 0.2 x 0.3 0.5 x 0.6 1.2 x 1.6 2.4 x 3.2 4.8 x 6.4 9.6 x 12.8

3.6mm 6mm 12mm 60mm

Focal Length is measured in mm. In general,

the lower the number, the wider the angle.

(2.5mm) = a wide angle of view

(12mm) = a narrow angle of view

Manual or Auto Iris in a camera is similar to that in the human eye. It controls the amount

light coming through the lens. It opens and closes as needed to regulate brightness for opti-

mal image clarity. A manual iris has to be set manually at the time of installation. This type of

lens is more suited for indoor areas with a constant light source such as shopping centers,

offices, and schools. Auto iris lenses are used in areas where the light is constantly changing.

These are more commonly used in parking lots and entry ways.

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Vonnic Standalone DVR Uživatelský manuál Strana 6