Lifecam Questions

With the Lifecam HD-3000, does the FOV angle change with resolution/aspect ratio change? I use 320x240 and want to find distance but want to calculate the horizontal FOV correctly(if someone can for me plz do). Plz help, thanks!

Please note that I am certainly not an expert on this and may be very wrong after my Google searching (please correct me if I am) but FOV should not change with aspect ratio and definitely not with resolution.

In order to calculate the angle mathematically:

2(arctan(d/(2f))

where d is the length (in millimeters) of the sensor or film and f is the focal length. You can read more about it here as I did.

The specs are not easily accessible so you may have to seek other solutions such as those outlined by Greg here.

If you want to measure this directly, there are a couple approaches. NI IMAQ has a calibration operation that uses a page of polka dots held in front of the camera to characterize the camera/lens distortions, field of view, etc.

A low-tech approach is to use a yard stick and a tape measure. Hold the yardstick in front of the camera, parallel to the camera sensor/lens. Move it back and forth until it goes from edge to edge. Use a tape measure to get the distance from the camera focal point to the yardstick. Some cameras have a small mark where the focal point is inside the camera, but you can use the distance to the lens or perhaps the center of the camera.

Now draw out a picture showing how the triangle 18" wide and distance away will give you the half-angle of your FOV.

Greg McKaskle

Making use of the search section of Chief Delphi located on the top bar may save you from having to wait for answers, especially now that the season has ended.

I would also suggest asking for formulas/explanations when things are unclear rather than solutions because it will benefit you in the long-term if you can do the math (and save the world!).