scroll zoom code

void LateUpdate ()
    {
        float scrolling = Input.GetAxis("Mouse ScrollWheel");
        Camera.main.orthographicSize = Mathf.Clamp (Camera.main.orthographicSize, 230, 730);

        if (scrolling > 0f && Camera.main.orthographicSize >= 230 && Camera.main.orthographicSize <= 730)
        {
            Camera.main.orthographicSize -= 30;
        }
        else if (scrolling < 0f && Camera.main.orthographicSize >= 230 && Camera.main.orthographicSize <= 730)
        {
            Camera.main.orthographicSize += 30;
        }