How to combine camera and a object?

Hi guys , I try to put a camera into a group . But , the scene become dark when I control the camera with OrbitControls.
this is my code:

 var playerGroup = new THREE.Group();
camera.renderOrder = 1000;
var controls = new THREE.OrbitControls(camera);

I’m afraid I’m unable to reproduce:

BTW: Setting the renderOrder of a camera does not make sense since a camera is not rendered.

Sorry,It can’t solve my problem…