func prepareCamera() {
   viewData.captureSession = AVCaptureSession()
   viewData.captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

   if let _ = try? viewData.captureDevice?.lockForConfiguration() {
      viewData.captureDevice?.isSubjectAreaChangeMonitoringEnabled = true
      viewData.captureDevice?.unlockForConfiguration()
   }
   if let device = viewData.captureDevice {
      if let input = try? AVCaptureDeviceInput(device: device) {
         viewData.captureSession?.addInput(input)
         viewData.stillImage = AVCapturePhotoOutput()
         if viewData.stillImage != nil {
            viewData.captureSession?.addOutput(viewData.stillImage!)
            if let max = viewData.captureDevice?.activeFormat.supportedMaxPhotoDimensions.last {
               viewData.stillImage?.maxPhotoDimensions = max
            }
         }
         showCamera()
      } else {
         print("Not Authorized")
      }
   } else {
      print("Not Authorized")
   }
}