Vuforia On Unity3D: Usage of Camera Focus modes?

I'm fidgeting with AR a bit, and reading through Vuforia's documentation I've found about the Camera Focus Modes.

I'm using a DSLR through SparkoCam to do some tests, and have found that using this on my "CameraController" script:

    if(!CameraDevice.Instance.SetFocusMode(CameraDevice.FocusMode.FOCUS_MODE_CONTINUOUSAUTO))
{
Debug.LogError("Device does not support AF.");
}


Always prompts that the device has AF enabled, even if I disable AF on the camera... because it seems Sparkocam does not have a way to tell the computer that AF is off.

So, I guess I'm a bit lost here. I can't query the CameraDevice for which Focus Mode is being used, and the article does not talk in depth about its differences (besides that "you have to touch the screen to refocus", for instance). Should be considered a good practice something along the lines of (Pseudocode incoming):

if (!setFocusModeContinuous()) {
if (!setFocusModeNotContinuous() {
/* ... */
Debug.LogError("Try to plug something that is not a pinhole camera, please");
closeProgram();
}
}


or does Vuforia already handles this and I can effectively ignore this unless I need some specific focus mode for whatever reason?