Security Cameras - Lens Chart

 


CCTV Visual Lens Comparison Chart

The following chart displays the comparison of CCTV lens with the regular 135mm film camera lens.


CCTV lens

 

Standard Camera

Focal Length

Angle

 

Focal Length

2.5mm

120°

1

1

3.6mm

92°

1

1

4.3mm

78°

1

1

6.0mm

53°

2

1

12mm

25°

1

1

25mm

18°

1

111

 

lens
size

Field of View (in ft.)

5 ft
away

10 ft
away

15 ft
away

25 ft
away

50 ft
away

100 ft
away

mm

w

h

w

h

w

h

w

h

w

h

w

h

3.6

7.5

5.2

15.1

10.4

22.6

15.6

37.7

26.1

75.4

52.1

151

104

6.0

3.8

2.9

7.7

5.7

11.5

8.6

19.2

14.4

38.4

28.7

77

57

8.0

2.9

2.1

5.7

4.3

8.6

6.4

14.4

10.7

28.7

21.3

57

43

12.0

1.9

1.5

3.9

3.0

5.8

4.5

9.7

7.5

19.4

14.9

39

30

 

Lux and low lighting chart

Condition

Illumination

Details

(FTCD)

(LUX)

Sunlight
Full Daylight
Overcast Day
Very Dark Day
Twilight
Deep Twilight

10,000
1,000
100
10
1
.1

107,527
10,752.7
1,075.3
107.53
10.75
1.08

Daylight
Range

Full Moon
Quarter Moon
Starlight
Overcast Night

.01
.001
.0001
.00001

.108
.0108
.0011
.0001

Low Light
Level Range


During the day the amount of illumination reaching a scene depends on the time of day and atmospheric conditions.  
Direct sunlight produces the highest-contrast scene, allowing maximum identification of objects.  
On a cloudy or overcast day, less light is received by the objects in the scene, resulting in less contrast.
To produce an optimum camera picture under the wide variation in light level (such as occurs when the sun is obscured by clouds), an automatic-iris camera system is required.Typically, scene illumination measured in foot-candles (ftcd) can vary over a range of 10,000 to 1 (or more), which exceeds the operating range of most cameras for producing good quality video images.   The chart above summarizes the light levels occurring under daylight and these low light level conditions.   The equivalent metric measure of light level (lux) compared with the English (ftcd) is given.