ios 9 AVCaptureDevice установка точки фокусировки

Я пытаюсь установить точку фокусировки с помощью фронтальной камеры.

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

    let screenSize = cameraView.bounds.size

    let frameSize:CGSize = view.frame.size

    if let touchPoint = touches.first {

        var location:CGPoint = touchPoint.locationInView(cameraView)

        print("Tap Location : X: (location.x), Y: (location.y)")

        if cameraManager.cameraDevice == .Front {
            print("Front camera is used")

            location.x = frameSize.width - location.x;
        }
        else {
            print("Back camera is used")
        }

        let x = location.x / frameSize.width
        let y = 1.0 - (location.x / frameSize.width)

        let focusPoint = CGPoint(x: x, y: y)

        print("POINT : X: (x), Y: (y)")


        let captureDevice = (AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo) as! [AVCaptureDevice]).filter{$0.position == .Front}.first

        if let device = captureDevice {
            do {
                try device.lockForConfiguration()

                let support:Bool = device.focusPointOfInterestSupported

                if support  {

                    print("focusPointOfInterestSupported: (support)")

                    device.focusPointOfInterest = focusPoint

                    // device.focusMode = .ContinuousAutoFocus
                    device.focusMode = .AutoFocus
                    // device.focusMode = .Locked

                    device.unlockForConfiguration()

                    print("Focus point was set successfully")
                }
                else{
                    print("focusPointOfInterestSupported is not supported: (support)")
                }
            }
            catch {
                // just ignore
                print("Focus point error")
            }
        }
    }
}

Он работает на iphone6 для задней камеры. Но, когда я включаю переднюю камеру, она молотит. focusPointOfInterestSupported всегда возвращает false.

Как я могу решить эту проблему. Могу ли я программно установить точку фокусировки?

Спасибо!