[Update]
Use the allowsEditing property on a UIImagePickerController
imagePickerController.allowsEditing = NO;
The previous answer was a bit hacked to use a code path that didn't show a button, but wasn't awesome.
[Previous answer]
In fact, you can avoid this without having to worry about setting up your own image capture from the AV Foundation.
Enabling the following will remove the need to display the Overview screen. All you have to do is put some own buttons and connect them to the corresponding functionality.
[self.imagePickerController setShowsCameraControls:NO]
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