AVCaptureVideoPreviewLayer not showing - objective-c

Question

The goal is to simply display live video input from the webcam.
The code is distilled from one of Apple's examples and it seems to be at least partially working since the led next to the camera lights up when running.
I ctrl-dragged from the view in the storyboard to the outlet property in the interface and it is connected as referencing outlet now but nothing shows up, not even the black background color is set.
Any idea where I'm going wrong?
Thanks for your help
Edit:
Actually it is working just as expected if I set a breakpoint at the [previewViewLayer addSublayer:self.previewLayer]; line and continue to run in the debugger. There has to be some kind of timing issue.
Interface:
#property (retain) AVCaptureDevice *videoDevice;
#property (retain) AVCaptureDeviceInput *videoDeviceInput;
#property (retain) AVCaptureSession *session;
#property (retain) AVCaptureVideoPreviewLayer *previewLayer;
#property (assign) IBOutlet NSView *previewView;
Implementation:
- (void)viewDidLoad {
[super viewDidLoad];
[self getDevice];
[self initSession];
}
- (void)initSession {
// Create a capture session
// self.session = [[AVCaptureSession alloc] init];
[self setSession:[[AVCaptureSession alloc] init]];
// Attach preview to session
CALayer *previewViewLayer = [self.previewView layer];
[previewViewLayer setBackgroundColor:CGColorGetConstantColor(kCGColorBlack)];
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
[self.previewLayer setFrame:[previewViewLayer bounds]];
[self.previewLayer setAutoresizingMask:kCALayerWidthSizable | kCALayerHeightSizable];
[previewViewLayer addSublayer:self.previewLayer];
// Start the session
[self.session startRunning];
// Create a device input for the device and add it to the session
NSError *error = nil;
AVCaptureDeviceInput *newVideoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:self.videoDevice error:&error];
[self.session addInput:newVideoDeviceInput];
self.videoDeviceInput = newVideoDeviceInput;
[self.session commitConfiguration];
}
- (void)getDevice {
NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice *device in devices) {
NSLog(#"Device name: %#", [device localizedName]);
self.videoDevice = device;
}
}

Answer 1

Solved:
I moved [self initSession];from - (void)viewDidLoadto - (void)viewDidLayout
Update:
I ran into more problems later with - (void)viewDidLayout so eventually I moved to - (void)viewDidAppear