I haven't checked whether this is illegal, but it worked for me.
If you want the UIImagePickerController to start(and stay) in Landscape orientation code:
//Initialize picker
UIImagePickerController * picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
//set Device to Landscape. This will give you a warning. I ignored it.
//warning: 'UIDevice' may not respond to '-setOrientation:'
[[UIDevice currentDevice] setOrientation:UIInterfaceOrientationLandscapeRight];
//Set Notifications so that when user rotates phone, the orientation is reset to landscape.
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
//Refer to the method didRotate:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(didRotate:)
name:@"UIDeviceOrientationDidChangeNotification" object:nil];
//Set the picker source as the camera
picker.sourceType = UIImagePickerControllerSourceTypeCamera;
//Bring in the picker view
[self presentModalViewController:picker animated:YES];
The method didRotate:
- (void) didRotate:(NSNotification *)notification
{
//Maintain the camera in Landscape orientation
[[UIDevice currentDevice] setOrientation:UIInterfaceOrientationLandscapeRight];
}