So I am attempting to capture from two cameras in openCV (python & windows 7). I capture from one camera just fine, youll also notice I am doing some funky stuff to the image but that doesn't matter. This is the code to attempt to use two

```
import cv
import time
cv.NamedWindow("camera", 1)
cv.NamedWindow("camera2", 1)
capture = cv.CaptureFromCAM(0)
capture2 = cv.CaptureFromCAM(1)
while True:
    img = cv.GetMat(cv.QueryFrame(capture))
    img2 = cv.GetMat(cv.QueryFrame(capture2))
    dst_image = cv.CloneMat(img)
    dst_image2 = cv.CloneMat(img2)
    cv.ConvertScale(img, dst_image, 255, -59745.0)
    cv.ConvertScale(img2, dst_image2, 255, -59745.0)
    cv.ShowImage("camera", dst_image)
    cv.ShowImage("camera2", dst_image2)
    if cv.WaitKey(10) == 27:
        cv.DestroyWindow("camera")
        cv.DestroyWindow("camera2")
        break

```

Rather simple. However it won't work. Upon trying to create the matrix from the second camera (second line of code in the loop), I am told that the capture is null. The cameras I am using are logitech and are the same model. 

Side note: I also couldnt find the command to count cameras connected in python, so if someone could refer me to that I'd much appreciate it.
--Ashley

EDIT:
It might also be useful to know that windows often prompts me to choose which camera I would like to use. I can't seem to avoid this behavior. Additionally I downloaded some security like software that successful runs both cameras at once. It is not open source or anything like that. So clearly, this is possible.