Poll: Would you be interested in an inexpensive Wide-Angle lens for the Axis Webcam?

[PhilBot]

Hi

I'm embarrased to say that even though I passed optics in physics I don't know how focal length relates to FOV.

Any recommendations on how to choose between so many options? What does the camera come with, and what direction do we move to get a wider view?

Phil.

Originally Posted by Greg McKaskle

http://www.edmundoptics.com/onlineca...productID=2196

The have several quality levels for lenses. This is the primary link I use.

Greg McKaskle

[MrForbes]

Originally Posted by PhilBot

Hi

I'm embarrased to say that even though I passed optics in physics I don't know how focal length relates to FOV.

Have you ever used an SLR camera with a zoom lens? the focal lengths are marked on the lens barrel and align with a pointer on the zoom adjustment, you can see the FOV change as you zoom in and out. A point and shoot camera might have the focal length range printed on the lens housing, and you can zoom from one to the other and see what happens.

(shorter focal length = wider FOV)

[Greg McKaskle]

What does the camera come with, and what direction do we move to get a wider view?

The camera has a 1/4 inch sensor and the default lens is a 4mm focal length. If you go to the URL of a calculator such as
http://www.123securityproducts.com/calculator.html
and type in the distance to the object along with your lens description, and it will tell you the extent of the image at that distance.

For example, with the default lens and sensor, it calculates that you have a viewing angle of 73 degrees and at 30 feet from the camera, the image goes from floor to twenty feet above, and the distance from the leftmost to rightmost object in the image is 27 feet. Meaning that from midfield, the camera image contains the entire driver area.
Type in a new lens focal length, and it updates the description of what is in the image. If you want to jog those neurons and look at the math behind the calculator, you may want to lookup angle of view rather than field of view on wikipedia. They are closely related, and the angle of view seems to be the better documented term.

Greg McKaskle