I constructed a matrix of focal lengths by the number of vertical and horizontal detents necessary to calculate the number of horizontal and vertical shots in a virtual FOV. For example, I want to know the number of shots for a mosaic of 120 degrees (wide) by 90 degrees (high) for a given camera/sensor and lens. However, the calculation assumed that I could preview the focal length of a lens in the camera display. Unfortunately I dont think that's possible with a Canon 40D, which is what I'm using. Is there anyway to display the focal length in the preview?

Thanks in advance.