IOS 8 How to control SCNCamera by myself

Question

I m developing a APP using SCNKit on iOS8.0 using Xcode Beta2.
I have some issues of controlling the camera of a scene.
I want the camera focus a point and rotate around the object only in the positive y direction
and have a parallel version with X-Z plane.
I know there is  useful tool to control the camera using build-in function called "allowsCameraControl".
This build-in function can allow user having a 360 degree version on a object .
I can't find a API to get what I want. So I tried to adjust the position and rotation of the camera by myself.
I create the camera as below. And I rewrite the camera's position and rotation (eulerAngles) to make the camera rotate around a point and focus it.
But I failed with this.
Is there a better way to do this?
     cameraPositionHandler = [SCNNode node];
    cameraPositionHandler.position = SCNVector3Make(0.f, 2.f, 5.f);
    cameraDefaultPosition = cameraPositionHandler.position;
    cameraPositionHandler.name = @"CameraPositionHandler";
    [scene.rootNode addChildNode:cameraPositionHandler];
    cameraYBasedRotationHandler = [SCNNode node];
    cameraYBasedRotationHandler.name = @"CameraYBasedRotationHandler";
    [cameraPositionHandler addChildNode:cameraYBasedRotationHandler];
    cameraXBasedRotationHandler = [SCNNode node];
    cameraXBasedRotationHandler.name = @"CameraXBasedRotationHandler";
    cameraXBasedRotationHandler.eulerAngles = SCNVector3Make(0, 0, 0);
    [cameraYBasedRotationHandler addChildNode:cameraXBasedRotationHandler];
    camera = [SCNNode node];
    camera.name = @"Camera";

Answer 1

Wait for iCloud Photo Library to be introduced later this year.  It should allow you to keep full resolution photos and videos in iCloud and access them from your devices without having to have them stored on your devices.  It will use your iCloud storage plan.