iphone - iDevice camera shows black instead of preview

Question

I am developing an app that captures images from iDevice's camera and upload it to web service.

NO problem everything is working fine except the device's camera. Device's camera is driving my crazy. I am using below code to allow user to capture images. Sometimes camera shows preview and sometimes doesn't. Instead of preview is just shows complete darkness on screen. If I switch from rear to front camera is starts working fine. I have even trying deleting all background apps from device and clearing as much memory as I could; still no luck and I am stuck. :(

- (IBAction)addNewImage:(id)sender
{
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate = self;

    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
    {
        // Take picture from camera
        imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;

        // set no to take as much pictures as user want.
        imagePicker.showsCameraControls = YES;

        // Show user the camera
        [self presentModalViewController:imagePicker
                                animated:YES];
    }
    else
    {
        imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        [self presentModalViewController:imagePicker
                                animated:YES];        
    }    
}

Answer 1

I have a customer who had this issue. They must have selected to not allow access to the camera. We had to change the camera privacy setting for the app in Settings. When we switched that back on, no more black camera screen.