iOS: Customize Back Button Transition Animation

I have a view controller (inherits from `UIViewController`) that has custom logic for presenting data. It can init a new view controller (of the same type) and display it using `[self.navigationController pushViewController:next animated:NO]` (where next is the newly instantiated controller), creating an experience of a "stack of views", using the navigation controller default back button to navigate up the stack. Now, before calling `pushViewController:animated:` I am able to customize the transition animation by calling `[self.navigationController.view.layer addAnimation:animation forKey:nil]`. This works wonderfully for "going down the stack" of views. But since navigation up the stack is done the default way with a default back button, the transition used is the default slide-fro-left animation which doesn't match my customized animation. How can I customize this transition animation? EDIT: I took the ideas given here and came up with: ``` UIBarButtonItem *back = [[UIBackButtonItem alloc] initWithTitle:@"\U000025C0\U0000FE0E" style:UIBarButtonItemStylePlain target:self action:@selector(back:)]; [self.navigationItem setLeftBarButtonItem:back] ``` And the transition: ``` - (IBAction)back:(id)sender { CATransiotion *animation = [CATransition animation]; animation.duration = 0.3f; amimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]; animation.type = kCATransitionMoveIn; [self.navigationController.view.layer addAnimation:animation forKey:nil]; [self.navigationController popViewControllerAnimated:NO]; } ``` The only downside is the appearance of the new back button which I'm willing to live with. Thanks for the answers :)