Present a UIImagePickerController results in temporary black screen

All,

I am developing an application that shows an initial page, then presents a UIImagePickerController with presentModalViewController:animated:.

After taking the photo, it returns to the initial page, dismiss the UIImagePickerController with dismissModalViewControllerAnimated:. Then save the photo and write a record in a table in SQLite database. It presents the UIImagePickerController again after triggered by tapping a button.

It works fine on iOS 4 and 5. But there is a little problem when running on iOS 6.

When the app re-presents the UIImagePickerController (that mean present and dismiss at least once before), the preview screen of the camera will be black for 5-6 seconds (for iOS 6 on iPhone 5, and 10-15 seconds for iOS 6 on iPhone 4 and 4S). And the console log shows the following message when the preview screen back to normal,

<Warning>: CoreAnimation: warning, deleted thread with uncommitted CATransaction; set CA_DEBUG_TRANSACTIONS=1 in environment to log backtraces.

I have already noticed that the old methods presentModalViewController:animated: and dismissModalViewControllerAnimated: are deprecated on iOS 6 and I have made necessary changes. But the problem continues.

Here is my code:

For presenting the UIImagePickerController:

NSString *requiredSystemVersion = version6_0;

if ([Utils checkCurrentOSVersionOlderThanVersion:requiredSystemVersion]) {

[[self navigationController] presentModalViewController:picker animated:YES];

} else {

[[self navigationController] presentViewController:picker animated:YES completion:NULL];

}

For dismissing the UIImagePickerController:

NSString *requiredSystemVersion = version6_0;

if ([UtilscheckCurrentOSVersionOlderThanVersion:requiredSystemVersion]) {

[[selfnavigationController] dismissModalViewControllerAnimated:YES];

} else {

[[selfnavigationController] dismissViewControllerAnimated:YEScompletion:NULL];

}

where checkCurrentOSVersionOlderThanVersion: is for checking the OS version is older than the 6.0.

XCode version: 4.2 on Max OS 10.6.8

Would anyone can lend a hand for helping on this issue? Or it is some default behavior on iOS 6?

Thanks in advance.

Dart