# Help with simple goniometrics

• Sep 5th 2010, 01:05 AM
mrtea
Help with simple goniometrics
Hi heres my problem -

tan(α/2) = (l/2)/d, hence
α = 2*atan(l/2d)

with this formula I can calculate the horizontal field-of-view of my camera.

I found it at this site - Determining the viewing angle of your camera

Only I havent a scientific calculator or the where with all to solve this!

I need to find a - the angle of view.
I know that l is the width - 2290mm
and I know that d is the distance - 5000mm

Any help from your forum members would be great! please save me any more days trawling endless websites trying to make sense of this!

Thanks
JayT

• Sep 5th 2010, 02:41 AM
Pim
Is your problem that you don't know how to compute this, or that you don't have a scientific calculator.
You can enter this in google: 2*atan(2290/(2*5000)) and Windows has a built in calculator, which you can expand using the "Scientific" option.
The answer you'll get is in radians, which you can convert to degrees by multiplying it by $\frac{360}{2\pi}$
• Sep 5th 2010, 04:12 AM
mrtea