I don't understand what is the difference between
`self.navigationcontroller.navigationitem` and `self.navigationitem`
i have navigation based application and in `viewDidLoad` method in `rootViewController` of navigationController I set the NavigationItem titleView to custom image by using this code

```
UIImageView* titleImage=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image.png"]];
self.navigationItem.titleView =titleImage;

```

by the way if i try to change titleview by this way 

```
UIImageView* titleImage=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image.png"]];
self.navigationcontroller.navigationItem.titleView =titleImage;

```

nothing was happened.
, and when navigationcontroller pushed the another view to the stack the titleview of navigationitem is cleared and reference sets to nil, and also i noticed that the references of **`self.navigationcontroller.navigationitem`** and **`self.navigationitem`** are not the same.