How to show iris(some says shutter) in Camera while capturing image in iPhone?

I have implemented camera in iPhone and taking images and save it in PhotoAlbum. Now what i want is when i save one image and make button enable for taking second image i want iris to be shown in between.So that 开发者_高级运维it feels excatly like Camera functionality of iPhone. How i do that please give some suggestion. Thanks

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Apps like Stachematic and Zombiematic actually got away with using this private API ...

CATransition *animation = [CATransition animation];
[animation setDelegate:self];
[animation setDuration:0.3];
animation.timingFunction = UIViewAnimationCurveEaseInOut;
[animation setType:@"cameraIris"];
[cameraView.layer addAnimation:animation forKey:nil];