AVCaptureDevice Low Light Boost Does Not work - ios

Question

The low light boost property of AVCaptureDevice is not enabling when it should. I am testing this on an iPhone 5 with iOS 6. Here's the code:
// finds a device that supports the video media type
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSArray *allDevices = [AVCaptureDevice devices];
for (AVCaptureDevice *currentDevice in allDevices) {
if (currentDevice.position == AVCaptureDevicePositionBack) {
device = currentDevice;
}
}
NSError *deviceError = nil;
if (device.isFlashAvailable){
[device lockForConfiguration:&deviceError];
device.flashMode = AVCaptureFlashModeAuto;
[device unlockForConfiguration];
}
if ([device respondsToSelector:#selector(isLowLightBoostSupported)]) {
if ([device lockForConfiguration:nil]) {
if (device.isLowLightBoostSupported)
device.automaticallyEnablesLowLightBoostWhenAvailable = YES;
[device unlockForConfiguration];
}
}
if ([device isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {
[device lockForConfiguration:&deviceError];
device.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
// CODE FOR device.exposurePointOfInterest determined from wherever the face is based off of the faceScan method
[device unlockForConfiguration];
}
AVCaptureDeviceInput *newVideoInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&deviceError];
AVCaptureStillImageOutput *newStillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:
AVVideoCodecJPEG, AVVideoCodecKey,
nil];
[newStillImageOutput setOutputSettings:outputSettings];
self.sess = [[AVCaptureSession alloc] init];
if ([self.sess canAddInput:newVideoInput]) {
[self.sess addInput:newVideoInput];
}
if ([self.sess canAddOutput:newStillImageOutput]) {
[self.sess addOutput:newStillImageOutput];
}
self.stillImageOutput = newStillImageOutput;
if (device.lowLightBoostEnabled) {
NSLog(#"ENABLED");
}
// register as an observer of changes to lowLightBoostEnabled
[device addObserver:self forKeyPath:#"automaticallyEnablesLowLightBoostWhenAvailable" options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld) context:NULL];
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
if ([keyPath isEqual:#"lowLightBoostEnabled"]) {
NSLog(#"lowLightBoostEnabled changed");
NSNumber *boostIsActiveValue = [change objectForKey:NSKeyValueChangeNewKey];
BOOL boostIsActive = boostIsActiveValue.boolValue;
NSLog(#"is low light boost currently active: %d", boostIsActive);
}
}
Can anyone give me any help? I've looked online but haven't found very conclusive results. I'd appreciate all the help I can get.

Answer 1

You need to lockForConfiguration, according to the docs (well, the header file):
if ([[self backFacingCamera] respondsToSelector:#selector(isLowLightBoostSupported)]) {
if ([[self backFacingCamera] lockForConfiguration:nil]) {
if ([self backFacingCamera].isLowLightBoostSupported)
[self backFacingCamera].automaticallyEnablesLowLightBoostWhenAvailable = YES;
[[self backFacingCamera] unlockForConfiguration];
}
}
Also, isLowLightBoostEnabled tells you whether or not the low light is actually being boosted, not whether it can be. That's the isLowLightBoostSupported selector, as above (to which only iOS 6 devices respond).