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RECOMMENDED: Excellent freeware lens calculator!

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I downloaded this calculator and found an error in the horizontal angle of view calculation.

 

It seems for any given parameters in this calculator

horizontal angle = vertical * 4/3. This is wrong!

 

In fact the correct formula for sensor with aspect ratio 4:3 is little bit more complicated:

Horizontal Angle = 2 arcsin( sin(VerticalAngle/2) * 4 / 3)

 

For example for camera with sensor format 1/3" and focal length 3mm

all other tools show Vertical angle = 61.9; Horizontal Angle = 77.3

in this CamTech calculator Vertical angle = 61.9; Horizontal Angle = 82.4

 

Please click on images to enlarge.

 

120718_1.jpg

 

Correct example (IP Video System Design Tool):

120718_2.jpg

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See also CCTV Design Lens Calculator. Together with usual functions of Lens Calculators, it offers several new tools, such as calculating field of view projections in 3D, simulating camera resolution using photos and images including megapixel cameras up to hundreds of megapixels and other.

 

CCTV Design Lens Calculator is free

 

186763_1.png

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If anyone needs the original program, I found it and uploaded to another file hosting company:

 

hxxp://www.sendspace. com/file/9b6rhd (change hxxp to http and delete space after the period)

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Lot's of broken links...

 

Is there any free and good software available?

Third post says it haves an error

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If anyone needs the original program, I found it and uploaded to another file hosting company:

 

hxxp://www.sendspace. com/file/9b6rhd (change hxxp to http and delete space after the period)

 

wow talk about making life difficult. Try following your link even changing the xx for tt

 

Life is just too short.

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Today, all Lens calculators and CCTV design software (except VideoCAD Professional 8.1) calculate view angles of wide angle lenses with errors, because they do not take into account the Lens distortion.

About Lens Distortion

 

271670_1.jpg

 

Additional errors are expected in calculating the view angles of modern cameras because of the image sensor size is considered in inches from the time of vidicons not taking into account existence of the modern image sensors with aspect ratios different from 4:3 and/or using not whole pixel area for scanning.

See Specifying active area size of the image sensor

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