Two questions:

1. Who's missing?
2. What's missing?

The first will answer the second, so let's start with the first.

The above is a shot from the climactic fight at the Fortress of Solitude in “Superman II,” in which we can see the three Kryptonian supervillains battling Superman, with Lois Lane watching. But where's Gene Hackman's Lex Luthor? That's who's missing.

Fans know this, most people don't, but 70-80 percent of “Superman II” was filmed alongside “Superman: The Movie”; and when the team reassembled to finish it in 1979, several of the most important elements were missing: cinematographer Geoffrey Unsworth had died in the interim (the first movie was in fact dedicated to him); director Richard Donner never played well with the Salkinds, the father-son producer team who owned cinematic rights to the Man of Steel, and had been replaced by director Richard Lester (“A Hard Day's Night”); and Gene Hackman, a Donner supporter, had opted not to come back.

So when scenes were reshot, Lester relied on subterfuge to hide Hackman's absence: a body double or voiceover. Cheap stuff. Or he wasn't in the shot. As he's not here.

But how does Hackman's absence answer the second question?

You need to look at what they're doing. The three Kryptonian supervillains are training energy beams from their hands at Superman, who's stopping them with his own hand. 

Energy beams from the hands? Right. That's not a Kryptonian superpower. Lester didn't care. In an earlier scene, one of the supervillains lifts a dude in the air by pointing at him. At the Fortress of Solitude, Superman throws the “S” symbol (or family crest) and it shrinkwraps Non. None of this was ever in the comic books, and none of it would have been allowed with Donner as director. His watchword on the set of “Superman” was verisimilitude. He had it practically tattooed on everyone's forehead.

And that, of course, is what's missing from the shot: verisimilitude.