title: Emulating the camera apps 'tap to focus'
body: <p>I am trying hard to emulate the basic functionality of the built in camera app. Thus far I have become stuck on the 'tap to focus' feature.</p>
  
  <p>I have a UIView from which I am collecting UITouch events when a single finger is tapped on the UIView. This following method is called but the camera focus &amp; the exposure are unchanged.</p>
  
  <pre><code>-(void)handleFocus:(UITouch*)touch
  { 
       if( [camera lockForConfiguration:nil] )
       {     
            CGPoint location = [touch locationInView:cameraView];
  
            if( [camera isFocusPointOfInterestSupported] )
                 camera.focusPointOfInterest = location;
  
            if( [camera isExposurePointOfInterestSupported] )
                 camera.exposurePointOfInterest = location;
  
  
            [camera unlockForConfiguration];
            [cameraView animFocus:location];
       }
  }
  </code></pre>
  
  <p>'camera' is my AVCaptureDevice &amp; it is non-nil. Can someone perhaps tell me where I am going wrong?</p>
  
  <p>Clues &amp; boos all welcome.</p>
  
  <p>M.</p>