UIView *videoView = [[UIView alloc] init];
...
AVCaptureSession *session = [[AVCaptureSession alloc] init];
AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
previewLayer.frame = videoView.bounds;
[videoView.layer addSublayer:previewLayer];
[session startRunning];