# Can I calculate sensor size from pixel dimensions and number (to find angle of view)?

I read up an equation on Wikipedia i.e. a camera's angle of view can be found from the following equation

``````angle of view = 2 arctan ( d / 2f )
``````

where f = focal length and d = size of film or sensor.

I am now trying to find the field of view of this camera https://www.ptgrey.com/flea2-14-mp-color-firewire-1394b-sony-icx267-camera. The size of the sensor / film is not given but what are given are the pixel size and the resolution. Would the sensor size simply be the pixel size * the number of pixels along the width / rows ? I also have only the focal length in pixels and was wondering how i can convert it to mm.

This is an image taken by that camera btw. Page 8 of their reference manual shows the sensor number (various sensors used): https://www.ptgrey.com/support/downloads/10117

Then look up that sensor size on data sheet on Google by searching for say:
sony icx424 sensor

Knowing sensor dimensions, then a calculator at http://www.scantips.com/lights/fieldofview.html will do the math.

Checking the Sony specifications, the image area of sensor is 6mm by 6.9mm. If this is the format used then armed with this data, I can calculate the angle of view yield for various focal lengths.

6mm lens 53.1⁰ vertical 59.8⁰ horizontal 74.6 diagonal

8mm lens 41.1⁰ vertical 46.7⁰ horizontal 59.5⁰ diagonal

10mm lens 33.4⁰ vertical 38.1⁰ horizontal 49.1⁰ diagonal

12mm lens 28.1⁰ vertical 32.1⁰ horizontal 41.7⁰ diagonal

15mm lens 22.5⁰ vertical 25.9⁰ horizontal 33.9⁰ diagonal

The size of the sensor / film is not given but what are given are the pixel size and the resolution. Would the sensor size simply be the pixel size * the number of pixels along the width / rows?

The answer depends on how precise you need to be. For a rough, ballpark figure, this will probably be fine. If you need it to be exact, no way.

I also have only the focal length in pixels and was wondering how i can convert it to mm.

"Focal length in pixels" is exceedingly weird. However, if you consider the equation you've given, you'll note that sensor size is divided by (twice the) focal length, which means that if you have both in the same units, they cancel out. (I expect that you actually have focal length in pixels because someone did this in reverse, with only pixel dimensions to start with. That would make me suspicious of that number, again for anything other than a ballpark idea.)

• I'd also check to see what the pixel size appears to be. If the focal length and sensor size proportions don't add up then something is wrong with the info. Nov 27 '16 at 1:57