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CCTV Lens Comparison Chart 
 
CCTV lens
 
Focal Length
Angle
 
2.5mm
120
https://cctvgold.com/assets/images/General/Lenscompare/2-5.gif
3.6mm
92
https://cctvgold.com/assets/images/General/Lenscompare/3-6.gif
4.3mm
78
https://cctvgold.com/assets/images/General/Lenscompare/4-3.gif
6.0mm
53
https://cctvgold.com/assets/images/General/Lenscompare/6-0.gif
12mm
25
https://cctvgold.com/assets/images/General/Lenscompare/12.gif
25mm
18
https://cctvgold.com/assets/images/General/Lenscompare/25.gif

https://cctvgold.com/assets/images/General/Lenscompare/5-100.jpg

Competitor's Website - Excellent Examples of Field of View Comparisons - Click Here

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

Lens Calculator - Try It!!!!

https://cctvgold.com/assets/images/General/Lenscompare/FOV.gif

Here is a link to an online lens calculator that will help you learn about various lens sizes and will help you decide what lens is appropriate for your camera.

Please note that not all lens sizes are available in every camera. For example, very wide field of vision lens do not always work in a night vision camera with LEDs as the LEDs will interfere with the wide view.

Which Security Camera Lens Should I Use?

How far you need to see will determine what security camera lens you should use to best fit your application. A 4mm lens will give a 70 degree angle of view with 35 feet of facial detail. This works great for residential or small office security camera applications. If you need to see further you would go with a higher powered lens. Keep in mind that the further you want to see will narrow the field of view of your picture.

A rule of thumb is that a 8mm lens is like a 4mm lens zoomed in 2 times. Similarly, a 16mm lens is like the 4mm lens zoomed in 4 times. For example, a 16mm lens would give you about a 15 degree angle of view focused at 35 ft.

What If I Do Not Know Exactly How Far I Need To See?

Instead of going with a fixed focus lens you can go with a varifocal lens. With a simple adjustment you can manually zoom in or zoom out and focus the camera to the exact distance needed to get a clear picture. Varifocal lenses come in all different sizes: (3.5-8mm; 9-22mm; and 5-50mm) just to name a few. This is the best option for large commercial applications because you can adjust the focal distance to what works just right.

What is a PTZ camera?

A Pan Tilt Zoom camera (PTZ) allows you to pan (back and forth), tilt (up and down), and zoom (focus in and out) your camera remotely. The PTZ is controlled using a remote PTZ controller or you can control it through most DVRs (look for PTZ support). The disadvantages of a PTZ camera is that they are very expensive (usually around $1000 without the controller). And all the moving parts make it susceptible to wear and breakdown.

There are some new digital versions of PTZ cameras just coming on the market that have no mechanical parts. These PTZs are very promising but are still a little too expensive to be practical for most uses. PTZ cameras require a data cable to be run to the camera in addition to the video and power cables. Unless you have a person who is watching the scene and adjusting the field of view of the camera based on what is going on its not as useful. Most times you are better off buying more of the non-PTZ cameras to continuously cover the area rather than a PTZ.

What is the difference between no iris and auto iris?

The iris controls how much light is let into the camera lens. In the old days, cameras came with no iris control. If you needed to control the light levels you would have to purchase a special lens. Nowadays, most cameras come with automatic shutters which perform the same function as the iris - controlling how much light is let into the camera. Unless you have an application with extreme light levels (like at a beach) you probably won't need a special lens with iris control.

Lux and low lighting chart

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
107,527.00
10,752.70
1,075.30
107.53
10.75
1.08
Daylight
Range
Full Moon
Quarter Moon
Starlight
Overcast Night
.01
.001
.0001
.00001
.1080
.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.

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