Camera never activates LowLightBoost on iPhone 5

I have the following code:

// Create the capture device

camera = [CameraManager cameraWithPosition:AVCaptureDevicePositionBack];

if (camera.lowLightBoostSupported) {

if ([camera lockForConfiguration:nil]) {

camera.automaticallyEnablesLowLightBoostWhenAvailable = YES;

[camera unlockForConfiguration];

}

}

But the lowLightBoost never activates, even if I put the device with the backside on the table so the preview image is pitch black.

- (void)captureOutput:(AVCaptureOutput *)captureOutput

didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer

fromConnection:(AVCaptureConnection *)connection

{

NSLog(@"LowLight active: %@ Camera lowlightWhenAvailable: %@",camera.isLowLightBoostEnabled ? @"true": @"false",camera.automaticallyEnablesLowLightBoostWhenAvailable ? @"true": @"false");

gives me

2013-10-25 10:21:53.179 aCoDriver[1019:668f] LowLight active: false Camera lowlightWhenAvailable: true

2013-10-25 10:21:53.429 aCoDriver[1019:668f] LowLight active: false Camera lowlightWhenAvailable: true

2013-10-25 10:21:53.679 aCoDriver[1019:668f] LowLight active: false Camera lowlightWhenAvailable: true

2013-10-25 10:21:53.929 aCoDriver[1019:668f] LowLight active: false Camera lowlightWhenAvailable: true