You do not have to determine if there is a camera looking at the model. This is not future proof - for example, you will not support the iPad 2 camera.
UIImagePickerController has a special method for determining camera availability:
+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType
Since sourceType is one of
UIImagePickerControllerSourceTypePhotoLibrary, UIImagePickerControllerSourceTypeCamera, UIImagePickerControllerSourceTypeSavedPhotosAlbum
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