Visual effects, have become a common practice in Hollywood nowadays, and while some may use practical means of executing a shot more than likely will end using some computer magic to enhance shots. Batman v Superman is no different as evidenced by this reel.
Snyder is currently tinkering with the visual effects of another DC film, Justice League, which has been in the post production side of filmmaking for some time and will continue on until every shot is perfected for viewers.
Source: Cruel Films
