Sample project for the article written for objc.io
The CameraController implements the camera controls using AVFoundation.
There are two types of live preview implemented, one with AVCapturePreviewLayer for full-automatic preview, and one with a GLKView for manual processing (as an example, the preview is filtered with a monochrome CIFilter). To switch between one or the other, change the class of the view controller embedded in the "Video Preview" container (see the view controllers that implement the CameraPreviewController protocol)