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Help and Explanation
FOV Calculator Tool and Distance Chart

Field of View (FOV) Calculator
Enter you ideal distance and width. The answer will be the closest mm lens to
achieve that goal. Or enter lens size and distance, which will give
you the width at that point.

Enter distance to object (in feet):
Enter width of picture (in feet): OR
Enter height of picture (in feet):
Enter size of lens (in millimeters):
Samples of Standard widths in feet
Size of LensFOV@ 25 ftFOV @50 ftFOV @100 ft
35mm3.46.913.7
25mm4.89.619.2
16mm7.51530
12mm102040
8mm153060
6mm204080
3.6mm33.366.7133.3

2.9mm

55110220


Below are sample pictures taken with different mm lenses at different distances to further assist you in selecting the best lens mm for your application. 3.6mm is by far the most common lens sold in surveillance cameras. All same mm lens cameras will vary slight with the field of view (FOV) depending on that particular manufacturer. The way a camera is actually built will have a direct impact on the degree of field of view. The calculator above will not give exact measurements for any camera. Just a very close approximation.

Certain other points to keep in mind are

1. The actual picture size will vary depending on whether you are viewing full screen on a TV or smaller screen on pc monitors using dvr software.

2. These pictures are in daylight. Night time viewing will vary significantly depending on the exact camera you purchase and how many LEDS are on the camera.

3. These very old pictures below were taken with our 400 lines of resolution 159 series camera. This means the camera you purchase today will more than likely be higher than 400 lines.


Long range 25mm lens; Has a 13.3 degree field of view.
This means that at 100 feet away the camera will view approx. 19.2 ft. span from left to right.

25mm
home security camera
Sign is 65 ft. away

Medium range 12mm lens Has a 28 degree field of view.
This means that at 100 feet away the camera will view. 40 ft. span from left to right,
at 50 ft. it will view approx. 20 ft. span. At 25 ft away it will view a 10 ft. span.


12mm

Sign is 65 ft. away

Medium range 6mm lens Has a 53 degree field of view.
This means that at 100 away it will view about 80 ft span. At 50 ft. it will view approx.
40 ft. span. At 20 ft. away it will view about a 20 ft. span.


6mm

Sign is 65 ft. away

Most popular range is the 3.6mm lens which has a 92 degree FOV.
At 100 ft away it will view about 133 ft span. At 50 ft. away it will view a
66 ft. span. At 25 ft. away, viewing span is about 33 ft.


3.6mm

Sign is 65 ft. away

Short range 2.97mm lens Has a 130 degree FOV. At 25 ft. away, viewing span
is about 55 ft. and at 65 ft. distance, viewing span is about 120 ft.


2.97mm

Sign is 65 ft. away

Cameras come with different lenses and this different lenses provide different FOVs (field of views). Depending on the lens on your camera, you may get a very narrow or a very wide FOV. The smaller the mm of the lens the wider of field of view. The larger the mm lens the narrower the field of view.