Camera turns black when I turn off flash light

Question

I use this code below to toggle on and off camera flash light

private void toggleFlash() {
    try {
        if(!flashOn) {
            captureRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH);
            captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
        } else {
            captureRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
            captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
        }
        captureSession.setRepeatingRequest(captureRequestBuilder.build(), null, handler);
        flashOn = !flashOn;
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

It works, but the issue is this. At first when I open the camera (without flash light), I can see the image preview from the camera clear, but when I toggle on the flash and toggle it off, the preview becomes more darker than the initial time of opening the camera.

I'm still new to the camera API but I guess the issue is coming from here

captureRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);

But I don't know the proper code to use to make the camera not to be dark. Anyone with a solution?

Answer 1

It's going black because you're turning off auto-exposure, and I suspect the default manual exposure and sensitivity values are so low that the image is very underexposed.

You don't need to turn auto-exposure OFF when you turn off the flash. To control the flash manually, you do need to make sure AE is not set to ON_AUTO_FLASH , ON_ALWAYS_FLASH , or ON_AUTO_FLASH_REDEYE , but that just means you can leave it as ON all the time, if you don't need automatic flash firing.

So just remove the bit about setting CONTROL_AE_MODE to CONTROL_AE_MODE_OFF

Answer 2

Torch and flash are two different setting in camera2. You can try and control flash with these setting.

On captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);

Off captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);