gistfile1.txt

- (void)focusWithMode:(AVCaptureFocusMode)focusMode exposeWithMode:(AVCaptureExposureMode)exposureMode atDevicePoint:(CGPoint)point monitorSubjectAreaChange:(BOOL)monitorSubjectAreaChange
{
	dispatch_async([self sessionQueue], ^{
		AVCaptureDevice *device = [[self videoDeviceInput] device];
		NSError *error = nil;
		if ([device lockForConfiguration:&error]) {
            if ([device isFocusPointOfInterestSupported] && [device isFocusModeSupported:focusMode]) {
				[device setFocusMode:focusMode];
				[device setFocusPointOfInterest:point];
			}
			if ([device isExposurePointOfInterestSupported] && [device isExposureModeSupported:exposureMode]) {
				[device setExposureMode:exposureMode];
				[device setExposurePointOfInterest:point];
			}
            if ([device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) {
                [device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];
            }
            if ([device isExposurePointOfInterestSupported] && [device isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
                [device setExposurePointOfInterest:point];
            }
            if ([device isLowLightBoostSupported]) {
                device.automaticallyEnablesLowLightBoostWhenAvailable = YES;
            }

			[device setSubjectAreaChangeMonitoringEnabled:monitorSubjectAreaChange];
			[device unlockForConfiguration];
		}
		else {
			NSLog(@"%@", error);
		}
	});
}