MousePosition with Iso camera movement

Hello everyone,

Im having a weird bug with my isometric camera, this returns the perfect point that i am clicking until my camera starts to follow my player. Camera is Orthographic with a 30x, 45y rotation.

Click code:

		Plane normal = new Plane (Vector3.up, new Vector3(0f, 0f, 0f));
		Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);


		Vector3 targetPoint = new Vector3 ();
		float hitDistance = 0f;
		if(normal.Raycast(ray, out hitDistance)) {
			targetPoint = ray.GetPoint(hitDistance);
		}


		Debug.DrawRay (characterTransform.position, targetPoint, Color.red, 200f);

Camera follow code:

void LateUpdate () {
		Vector3 targetCamPos = target.position + offset;
		transform.position = Vector3.Lerp (transform.position, targetCamPos, smoothing * Time.deltaTime);
}

For anyone having the same issue the solution in the end was i had to subtract the camera position from the target point, I have no idea why this is but if someone could enlighten me that would be great. Thanks