What is the baseline of a stereo camera?

The baseline (distance between both cameras) will influence the depth range that you can observe with a stereo camera, and also your depth resolution. The same also applies to the focal length of the lenses that you use.

Assuming that you process a disparity range with a constant size, then the following rules apply:

• Increasing the baseline will increase your depth resolution, but will also increase the minimum distance to the camera
• Increasing the focal length will also increase the depth resolution and minimum distance to the camera, but also reduce the field of view.

This relationship can be studied with the following online calculator: https://nerian.com/support/resources/calculator/

You're apparently dealing with stereo, where the baseline is (at least normally) the distance between the two lenses.

I believe

Z (depth) = (focalLength * baseline) / disparity

Other coordinates can be found here: http://www.ptgrey.com/support/kb/index.asp?a=4&q=63&ST=